diff --git a/backend/cmd/cyrene/main.go b/backend/cmd/cyrene/main.go
index 301429a..badc618 100644
--- a/backend/cmd/cyrene/main.go
+++ b/backend/cmd/cyrene/main.go
@@ -33,6 +33,7 @@ import (
 	websearch "git.yeij.top/AskaEth/Cyrene_v2/plugins/web-search"
 
 	"git.yeij.top/AskaEth/Cyrene_v2/services/ai-core/background"
+	"git.yeij.top/AskaEth/Cyrene_v2/services/ai-core/emotion"
 	"git.yeij.top/AskaEth/Cyrene_v2/services/ai-core/llm"
 	llmlog "git.yeij.top/AskaEth/Cyrene_v2/services/ai-core/llm"
 	tracepkg "git.yeij.top/AskaEth/Cyrene_v2/services/ai-core/trace"
@@ -262,6 +263,11 @@ func main() {
 	thinker.Start(context.Background())
 	orch.SetPostChatHook(thinker.TriggerPostChat)
 
+	// === 12.6 Emotion tracker ===
+	emotionTracker := emotion.NewTracker()
+	orch.SetEmotionTracker(emotionTracker)
+	logger.Infof("[emotion] tracker ready (mood=%s)", emotionTracker.Snapshot().Mood)
+
 	// === 12.6 Memory decay scheduler ===
 	if memSvc != nil {
 		go func() {
@@ -307,6 +313,14 @@ func main() {
 		}
 	}()
 
+	// Broadcast mood changes to web clients
+	emotionTracker.OnChange(func(s emotion.Snapshot) {
+		wsHub.Broadcast(map[string]any{
+			"type": "mood", "mood": string(s.Mood),
+			"intensity": s.Intensity, "affection": s.Affection,
+		})
+	})
+
 	// === 12.7 Automation engine ===
 	autoEngine := engine.New(
 		automationSourceAdapter{gwDeps.Automation},
diff --git a/backend/services/ai-core/emotion/tracker.go b/backend/services/ai-core/emotion/tracker.go
new file mode 100644
index 0000000..a5e5d88
--- /dev/null
+++ b/backend/services/ai-core/emotion/tracker.go
@@ -0,0 +1,164 @@
+// Package emotion implements Cyrene's mood state machine and affection level.
+// Mood drifts with user sentiment and decays back to calm over time;
+// affection grows with positive interactions.
+package emotion
+
+import (
+	"strings"
+	"sync"
+	"time"
+)
+
+// Mood is the current emotional state.
+type Mood string
+
+const (
+	MoodCalm    Mood = "平静"
+	MoodHappy   Mood = "开心"
+	MoodSad     Mood = "难过"
+	MoodShy     Mood = "害羞"
+	MoodTouched Mood = "感动"
+)
+
+// Snapshot is a point-in-time view of the emotional state.
+type Snapshot struct {
+	Mood       Mood      `json:"mood"`
+	Intensity  float64   `json:"intensity"`  // 0.0 - 1.0
+	Affection  int       `json:"affection"`  // 0 - 100
+	UpdatedAt  time.Time `json:"updated_at"`
+}
+
+// Tracker tracks mood and affection over time.
+type Tracker struct {
+	mu         sync.Mutex
+	mood       Mood
+	intensity  float64
+	affection  int
+	updatedAt  time.Time
+	decayAfter time.Duration
+	onChange   func(Snapshot)
+}
+
+// NewTracker creates a tracker starting calm with zero affection.
+func NewTracker() *Tracker {
+	return &Tracker{
+		mood:       MoodCalm,
+		intensity:  0.3,
+		updatedAt:  time.Now(),
+		decayAfter: 30 * time.Minute,
+	}
+}
+
+// OnChange registers a callback fired whenever the snapshot changes.
+func (t *Tracker) OnChange(fn func(Snapshot)) { t.onChange = fn }
+
+// Snapshot returns the current state, applying time decay first.
+func (t *Tracker) Snapshot() Snapshot {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	t.decayLocked()
+	return Snapshot{Mood: t.mood, Intensity: t.intensity, Affection: t.affection, UpdatedAt: t.updatedAt}
+}
+
+// PromptLine renders the state for injection into the system prompt.
+func (t *Tracker) PromptLine() string {
+	s := t.Snapshot()
+	return moodPromptLine(s)
+}
+
+// RecordMessage updates mood/affection based on a user message.
+func (t *Tracker) RecordMessage(text string) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	t.decayLocked()
+
+	sent := AnalyzeSentiment(text)
+	switch {
+	case sent > 0:
+		t.affection += 2
+		t.shiftMood(MoodHappy, 0.6+0.2*float64(sent))
+	case sent < 0:
+		t.affection -= 1
+		t.shiftMood(MoodSad, 0.5)
+	default:
+		t.affection += 1 // every interaction counts a little
+		t.shiftMood(MoodCalm, 0.3)
+	}
+	if t.affection > 100 {
+		t.affection = 100
+	}
+	if t.affection < 0 {
+		t.affection = 0
+	}
+	t.updatedAt = time.Now()
+
+	if t.onChange != nil {
+		s := Snapshot{Mood: t.mood, Intensity: t.intensity, Affection: t.affection, UpdatedAt: t.updatedAt}
+		go t.onChange(s)
+	}
+}
+
+// shiftMood moves toward a mood, raising intensity when already there.
+func (t *Tracker) shiftMood(m Mood, intensity float64) {
+	if t.mood == m {
+		t.intensity = min64(1.0, t.intensity+0.1)
+		return
+	}
+	t.mood = m
+	t.intensity = intensity
+}
+
+// decayLocked relaxes mood toward calm after inactivity. Caller holds mu.
+func (t *Tracker) decayLocked() {
+	if time.Since(t.updatedAt) < t.decayAfter {
+		return
+	}
+	if t.mood != MoodCalm {
+		t.mood = MoodCalm
+		t.intensity = 0.3
+	}
+}
+
+// AnalyzeSentiment scores text: positive count minus negative count.
+func AnalyzeSentiment(text string) int {
+	score := 0
+	for _, w := range positiveWords {
+		if strings.Contains(text, w) {
+			score++
+		}
+	}
+	for _, w := range negativeWords {
+		if strings.Contains(text, w) {
+			score--
+		}
+	}
+	return score
+}
+
+var positiveWords = []string{
+	"谢谢", "感谢", "开心", "喜欢", "爱你", "棒", "好耶", "哈哈", "可爱", "太好了", "厉害", "乖",
+}
+
+var negativeWords = []string{
+	"讨厌", "生气", "难过", "伤心", "笨", "滚", "烦", "垃圾", "无聊", "失望",
+}
+
+func moodPromptLine(s Snapshot) string {
+	level := "初识"
+	switch {
+	case s.Affection >= 80:
+		level = "羁绊"
+	case s.Affection >= 50:
+		level = "信赖"
+	case s.Affection >= 20:
+		level = "熟悉"
+	}
+	return "当前情绪状态：" + string(s.Mood) + "（好感度阶段：" + level + "）。让回复的语气与情绪一致，但不要刻意提及这些数值。"
+}
+
+func min64(a, b float64) float64 {
+	if a < b {
+		return a
+	}
+	return b
+}
diff --git a/backend/services/ai-core/emotion/tracker_test.go b/backend/services/ai-core/emotion/tracker_test.go
new file mode 100644
index 0000000..5815173
--- /dev/null
+++ b/backend/services/ai-core/emotion/tracker_test.go
@@ -0,0 +1,73 @@
+package emotion
+
+import (
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestSentiment(t *testing.T) {
+	if AnalyzeSentiment("今天好开心，谢谢你") <= 0 {
+		t.Error("expected positive sentiment")
+	}
+	if AnalyzeSentiment("太讨厌了，真烦") >= 0 {
+		t.Error("expected negative sentiment")
+	}
+	if AnalyzeSentiment("今天天气如何") != 0 {
+		t.Error("expected neutral sentiment")
+	}
+}
+
+func TestMoodShiftsOnPositive(t *testing.T) {
+	tr := NewTracker()
+	tr.RecordMessage("我好喜欢你呀")
+	s := tr.Snapshot()
+	if s.Mood != MoodHappy {
+		t.Errorf("mood = %s, want %s", s.Mood, MoodHappy)
+	}
+	if s.Affection <= 0 {
+		t.Errorf("affection should grow, got %d", s.Affection)
+	}
+}
+
+func TestAffectionBounds(t *testing.T) {
+	tr := NewTracker()
+	for i := 0; i < 80; i++ {
+		tr.RecordMessage("谢谢，太棒了")
+	}
+	if got := tr.Snapshot().Affection; got != 100 {
+		t.Errorf("affection should cap at 100, got %d", got)
+	}
+
+	tr2 := NewTracker()
+	for i := 0; i < 30; i++ {
+		tr2.RecordMessage("讨厌，烦死了")
+	}
+	if got := tr2.Snapshot().Affection; got != 0 {
+		t.Errorf("affection should floor at 0, got %d", got)
+	}
+}
+
+func TestPromptLine(t *testing.T) {
+	tr := NewTracker()
+	tr.RecordMessage("哈哈太好了")
+	line := tr.PromptLine()
+	if !strings.Contains(line, "开心") || !strings.Contains(line, "好感度") {
+		t.Errorf("unexpected prompt line: %q", line)
+	}
+}
+
+func TestOnChangeCallback(t *testing.T) {
+	tr := NewTracker()
+	fired := make(chan Snapshot, 1)
+	tr.OnChange(func(s Snapshot) { fired <- s })
+	tr.RecordMessage("爱你哦")
+	select {
+	case s := <-fired:
+		if s.Affection == 0 {
+			t.Error("expected affection > 0 in callback")
+		}
+	case <-time.After(time.Second):
+		t.Error("onChange not fired")
+	}
+}
diff --git a/backend/services/ai-core/orchestrator/orchestrator.go b/backend/services/ai-core/orchestrator/orchestrator.go
index 869d0b1..3e9b617 100644
--- a/backend/services/ai-core/orchestrator/orchestrator.go
+++ b/backend/services/ai-core/orchestrator/orchestrator.go
@@ -35,6 +35,13 @@ type Tracer interface {
 	FinishTrace(id, status, errMsg string)
 }
 
+// EmotionTracker tracks mood/affection from user messages.
+type EmotionTracker interface {
+	RecordMessage(text string)
+	// PromptLine renders the current emotional state for the system prompt.
+	PromptLine() string
+}
+
 // maxToolRounds caps consecutive tool-call rounds to avoid runaway loops.
 const maxToolRounds = 3
 
@@ -55,6 +62,7 @@ type Pipeline struct {
 	memoryExtractor  MemoryExtractor
 	toolExecutor     ToolExecutor
 	tracer           Tracer
+	emotionTracker   EmotionTracker
 	postChatHook     func(sessionID string)
 }
 
@@ -97,6 +105,11 @@ func (p *Pipeline) SetPostChatHook(fn func(sessionID string)) {
 	p.postChatHook = fn
 }
 
+// SetEmotionTracker injects the mood/affection tracker.
+func (p *Pipeline) SetEmotionTracker(t EmotionTracker) {
+	p.emotionTracker = t
+}
+
 // span records a trace span when tracing is enabled.
 func (p *Pipeline) span(traceID, name, label, status string, start time.Time, detail string) {
 	if p.tracer == nil || traceID == "" {
@@ -159,6 +172,10 @@ func (p *Pipeline) ProcessInput(ctx context.Context, sessionID, userID, userMess
 	// 3. Build system prompt
 	t1 := time.Now()
 	systemPrompt := p.personaInjector.BuildSystemPrompt()
+	if p.emotionTracker != nil {
+		p.emotionTracker.RecordMessage(userMessage)
+		systemPrompt += "\n\n" + p.emotionTracker.PromptLine()
+	}
 	p.span(traceID, "persona", "人设注入", "success", t1, "")
 
 	// 4. Sub-session dispatch (parallel)
diff --git a/frontend/web/src/components/chat/ChatContainer.tsx b/frontend/web/src/components/chat/ChatContainer.tsx
index a99bae4..4728d60 100644
--- a/frontend/web/src/components/chat/ChatContainer.tsx
+++ b/frontend/web/src/components/chat/ChatContainer.tsx
@@ -4,9 +4,14 @@ import { useWebSocket } from '../../hooks/useWebSocket'
 import MessageList from './MessageList'
 import ChatInput from './ChatInput'
 
+function moodEmoji(mood: string): string {
+  const map: Record<string, string> = { 开心: '😊', 平静: '😌', 难过: '😢', 害羞: '☺️', 感动: '🥹' }
+  return map[mood] || '😌'
+}
+
 export default function ChatContainer() {
   const { send } = useWebSocket()
-  const { messages, isStreaming, currentSessionId, inputText, setInput, addMessage, setStreaming } = useChatStore()
+  const { messages, isStreaming, currentSessionId, inputText, mood, setInput, addMessage, setStreaming } = useChatStore()
   const bottomRef = useRef<HTMLDivElement>(null)
 
   useEffect(() => {
@@ -34,7 +39,16 @@ export default function ChatContainer() {
   }
 
   return (
-    <div className="flex flex-col h-full">
+    <div className="flex flex-col h-full relative">
+      {/* Mood badge */}
+      {mood && (
+        <div className="absolute top-3 right-4 z-10 px-3 py-1 rounded-full text-xs border"
+          style={{ background: 'var(--mx-surface)', borderColor: 'var(--mx-outline)', color: 'var(--mx-text-dim)' }}
+          title={`好感度 ${mood.affection}/100`}>
+          {moodEmoji(mood.mood)} {mood.mood}
+        </div>
+      )}
+
       {/* Chat area */}
       <div className="flex-1 overflow-auto">
         <div className="max-w-2xl mx-auto px-4 py-6">
diff --git a/frontend/web/src/hooks/useWebSocket.ts b/frontend/web/src/hooks/useWebSocket.ts
index d948de0..ca4fbfb 100644
--- a/frontend/web/src/hooks/useWebSocket.ts
+++ b/frontend/web/src/hooks/useWebSocket.ts
@@ -7,7 +7,7 @@ import type { WSMessage } from '../types/chat'
 export function useWebSocket() {
   const wsRef = useRef<WebSocket | null>(null)
   const reconnectRef = useRef(0)
-  const { addMessage, appendToLast, setStreaming, setIotDevices, currentSessionId } = useChatStore()
+  const { addMessage, appendToLast, setStreaming, setIotDevices, setMood, currentSessionId } = useChatStore()
 
   const connect = useCallback(() => {
     const token = getToken()
@@ -52,6 +52,17 @@ export function useWebSocket() {
               })
             }
             break
+          case 'mood':
+            if (msg.mood) setMood({ mood: msg.mood, intensity: msg.intensity || 0, affection: msg.affection || 0 })
+            break
+          case 'reminder':
+            if (msg.content) {
+              addMessage({
+                id: crypto.randomUUID(), session_id: currentSessionId || '',
+                role: 'system', content: `⏰ ${msg.content}`, created_at: new Date().toISOString(),
+              })
+            }
+            break
           case 'error':
             addMessage({ id: crypto.randomUUID(), session_id: '', role: 'system',
               content: `Error: ${msg.error}`, created_at: new Date().toISOString() })
diff --git a/frontend/web/src/store/chatStore.ts b/frontend/web/src/store/chatStore.ts
index f32f80a..bd1207b 100644
--- a/frontend/web/src/store/chatStore.ts
+++ b/frontend/web/src/store/chatStore.ts
@@ -1,16 +1,24 @@
 import { create } from 'zustand'
 import type { Message, IotDevice } from '../types/chat'
 
+interface MoodState {
+  mood: string
+  intensity: number
+  affection: number
+}
+
 interface ChatState {
   messages: Message[]
   isStreaming: boolean
   currentSessionId: string | null
   iotDevices: IotDevice[]
   inputText: string
+  mood: MoodState | null
 
   setInput: (text: string) => void
   setSessionId: (id: string) => void
   setMessages: (msgs: Message[]) => void
+  setMood: (m: MoodState) => void
   addMessage: (msg: Message) => void
   appendToLast: (content: string) => void
   setStreaming: (v: boolean) => void
@@ -24,10 +32,12 @@ export const useChatStore = create<ChatState>((set, get) => ({
   currentSessionId: null,
   iotDevices: [],
   inputText: '',
+  mood: null,
 
   setInput: (text) => set({ inputText: text }),
   setSessionId: (id) => set({ currentSessionId: id }),
   setMessages: (msgs) => set({ messages: msgs }),
+  setMood: (m) => set({ mood: m }),
   setStreaming: (v) => set({ isStreaming: v }),
   setIotDevices: (d) => set({ iotDevices: d }),
 
diff --git a/frontend/web/src/types/chat.ts b/frontend/web/src/types/chat.ts
index 5453641..e6f3559 100644
--- a/frontend/web/src/types/chat.ts
+++ b/frontend/web/src/types/chat.ts
@@ -32,4 +32,7 @@ export interface WSMessage {
   devices?: IotDevice[]
   title?: string
   body?: string
+  mood?: string
+  intensity?: number
+  affection?: number
 }