diff --git a/web/src/components/AccountSettingsComponent.vue b/web/src/components/AccountSettingsComponent.vue
index a0beea2e..1760042c 100644
--- a/web/src/components/AccountSettingsComponent.vue
+++ b/web/src/components/AccountSettingsComponent.vue
@@ -106,8 +106,7 @@ import { message } from 'ant-design-vue'
 import { CircleUser, RefreshCw, Upload } from 'lucide-vue-next'
 import ApiKeyManagementComponent from '@/components/ApiKeyManagementComponent.vue'
 import { useUserStore } from '@/stores/user'
-
-const DEFAULT_AVATAR_URL = 'https://xerrors.oss-cn-shanghai.aliyuncs.com/github/default.jpeg'
+import { generatePixelAvatar } from '@/utils/pixelAvatar'
 
 const userStore = useUserStore()
 const avatarUploading = ref(false)
@@ -117,7 +116,6 @@ const editingField = ref('')
 const usernameInput = ref(null)
 const phoneInput = ref(null)
 const avatarLoadFailed = ref(false)
-const defaultAvatarLoadFailed = ref(false)
 const profileDraft = reactive({
   username: '',
   phone_number: ''
@@ -125,8 +123,7 @@ const profileDraft = reactive({
 
 const avatarSrc = computed(() => {
   if (userStore.avatar && !avatarLoadFailed.value) return userStore.avatar
-  if (!defaultAvatarLoadFailed.value) return DEFAULT_AVATAR_URL
-  return ''
+  return generatePixelAvatar(userStore.uid)
 })
 
 const userRoleText = computed(() => {
@@ -150,9 +147,7 @@ const syncProfileDraft = () => {
 const handleAvatarError = () => {
   if (userStore.avatar && !avatarLoadFailed.value) {
     avatarLoadFailed.value = true
-    return false
   }
-  defaultAvatarLoadFailed.value = true
   return false
 }
 
@@ -276,7 +271,6 @@ const handleAvatarChange = async (info) => {
     avatarUploading.value = true
     await userStore.uploadAvatar(info.file.originFileObj || info.file)
     avatarLoadFailed.value = false
-    defaultAvatarLoadFailed.value = false
     message.success('头像上传成功！')
   } catch (error) {
     console.error('头像上传失败:', error)
@@ -290,7 +284,6 @@ watch(
   () => userStore.avatar,
   () => {
     avatarLoadFailed.value = false
-    defaultAvatarLoadFailed.value = false
   }
 )
 
diff --git a/web/src/components/UserInfoComponent.vue b/web/src/components/UserInfoComponent.vue
index d6eb8d3a..2064fa34 100644
--- a/web/src/components/UserInfoComponent.vue
+++ b/web/src/components/UserInfoComponent.vue
@@ -74,14 +74,13 @@ import DebugComponent from '@/components/DebugComponent.vue'
 import { message } from 'ant-design-vue'
 import { CircleUser, BookOpen, Sun, Moon, LogOut, Settings, Terminal } from 'lucide-vue-next'
 import { useThemeStore } from '@/stores/theme'
+import { generatePixelAvatar } from '@/utils/pixelAvatar'
 
 const router = useRouter()
 const userStore = useUserStore()
 const themeStore = useThemeStore()
 const slots = useSlots()
 
-const DEFAULT_AVATAR_URL = 'https://xerrors.oss-cn-shanghai.aliyuncs.com/github/default.jpeg'
-
 // 调试面板状态
 const showDebug = ref(false)
 
@@ -89,28 +88,23 @@ const showDebug = ref(false)
 const { openSettingsModal } = inject('settingsModal', {})
 
 const avatarLoadFailed = ref(false)
-const defaultAvatarLoadFailed = ref(false)
 
-// 用户头像不可用时回退到公共默认头像；默认头像异常时再显示图标占位。
+// 用户头像不可用时回退到基于 UID 生成的本地像素头像。
 const avatarSrc = computed(() => {
   if (userStore.avatar && !avatarLoadFailed.value) return userStore.avatar
-  if (!defaultAvatarLoadFailed.value) return DEFAULT_AVATAR_URL
-  return ''
+  return generatePixelAvatar(userStore.uid)
 })
 
 const handleAvatarError = () => {
   if (userStore.avatar && !avatarLoadFailed.value) {
     avatarLoadFailed.value = true
-    return
   }
-  defaultAvatarLoadFailed.value = true
 }
 
 watch(
   () => userStore.avatar,
   () => {
     avatarLoadFailed.value = false
-    defaultAvatarLoadFailed.value = false
   }
 )
 
diff --git a/web/src/components/UserManagementComponent.vue b/web/src/components/UserManagementComponent.vue
index 5a18d088..3c81b1fa 100644
--- a/web/src/components/UserManagementComponent.vue
+++ b/web/src/components/UserManagementComponent.vue
@@ -73,15 +73,7 @@
               <div class="card-header">
                 <div class="user-info-main">
                   <div class="user-avatar">
-                    <img
-                      v-if="user.avatar"
-                      :src="user.avatar"
-                      :alt="user.username"
-                      class="avatar-img"
-                    />
-                    <div v-else class="avatar-placeholder">
-                      {{ user.username.charAt(0).toUpperCase() }}
-                    </div>
+                    <img :src="getUserAvatarSrc(user)" :alt="user.username" class="avatar-img" />
                   </div>
                   <div class="user-info-content">
                     <div class="name-tag-row">
@@ -279,6 +271,7 @@ import {
   MoreVertical
 } from 'lucide-vue-next'
 import { formatDateTime } from '@/utils/time'
+import { generatePixelAvatar } from '@/utils/pixelAvatar'
 
 const userStore = useUserStore()
 
@@ -437,6 +430,8 @@ watch(
 // 格式化时间显示
 const formatTime = (timeStr) => formatDateTime(timeStr)
 
+const getUserAvatarSrc = (user) => user.avatar || generatePixelAvatar(user.uid)
+
 const isUserDeleteDisabled = (user) =>
   user.id === userStore.userId ||
   (user.role === 'superadmin' && userStore.userRole !== 'superadmin')
@@ -832,11 +827,6 @@ onMounted(async () => {
                   object-fit: cover;
                 }
 
-                .avatar-placeholder {
-                  color: var(--gray-600);
-                  font-weight: 500;
-                  font-size: 14px;
-                }
               }
 
               .user-info-content {
diff --git a/web/src/components/dashboard/FeedbackModalComponent.vue b/web/src/components/dashboard/FeedbackModalComponent.vue
index f08ec440..19026e46 100644
--- a/web/src/components/dashboard/FeedbackModalComponent.vue
+++ b/web/src/components/dashboard/FeedbackModalComponent.vue
@@ -19,7 +19,7 @@
         <!-- 卡片头部：用户信息和反馈类型 -->
         <div class="card-header">
           <div class="user-info">
-            <a-avatar :src="feedback.avatar" :size="32" class="user-avatar">
+            <a-avatar :src="getFeedbackAvatarSrc(feedback)" :size="32" class="user-avatar">
               {{ feedback.username ? feedback.username.charAt(0).toUpperCase() : 'U' }}
             </a-avatar>
             <div class="user-details">
@@ -116,6 +116,7 @@ import { message } from 'ant-design-vue'
 import { LikeOutlined, DislikeOutlined, ClockCircleOutlined } from '@ant-design/icons-vue'
 import { dashboardApi } from '@/apis/dashboard_api'
 import { formatFullDateTime } from '@/utils/time'
+import { generatePixelAvatar } from '@/utils/pixelAvatar'
 
 // 常量配置
 const CONFIG = {
@@ -211,6 +212,8 @@ const loadFeedbacks = async () => {
   }
 }
 
+const getFeedbackAvatarSrc = (feedback) => feedback.avatar || generatePixelAvatar(feedback.uid)
+
 // 格式化完整日期
 const formatFullDate = (dateString) => formatFullDateTime(dateString)
 
diff --git a/web/src/utils/__tests__/pixelAvatar.test.js b/web/src/utils/__tests__/pixelAvatar.test.js
new file mode 100644
index 00000000..986039d3
--- /dev/null
+++ b/web/src/utils/__tests__/pixelAvatar.test.js
@@ -0,0 +1,43 @@
+import assert from 'node:assert/strict'
+import { generatePixelAvatar } from '../pixelAvatar.js'
+
+const decodeAvatarSvg = (avatar) => decodeURIComponent(avatar.replace('data:image/svg+xml,', ''))
+
+const run = () => {
+  {
+    const first = generatePixelAvatar('user-001')
+    const second = generatePixelAvatar('user-001')
+    assert.equal(first, second, 'Same ID should generate the same avatar')
+    console.log('T1 Stable output: PASS')
+  }
+
+  {
+    const first = generatePixelAvatar('user-001')
+    const second = generatePixelAvatar('user-002')
+    assert.notEqual(first, second, 'Different IDs should generate different avatars')
+    console.log('T2 Different IDs: PASS')
+  }
+
+  {
+    const avatar = generatePixelAvatar('user-003')
+    assert.ok(avatar.startsWith('data:image/svg+xml,'), 'Should return an SVG data URL')
+    console.log('T3 Data URL prefix: PASS')
+  }
+
+  {
+    const svg = decodeAvatarSvg(generatePixelAvatar('user-004'))
+    assert.ok(svg.includes('<svg'), 'Decoded output should contain an SVG tag')
+    assert.ok(svg.includes('<rect'), 'Decoded output should contain pixel rects')
+    console.log('T4 Decodable SVG: PASS')
+  }
+
+  {
+    assert.throws(() => generatePixelAvatar(''), /requires an id/, 'Empty ID should be treated as invalid data')
+    assert.throws(() => generatePixelAvatar(null), /requires an id/, 'Null ID should be treated as invalid data')
+    console.log('T5 Missing ID fails: PASS')
+  }
+
+  console.log('\nAll 5 pixel avatar tests passed!')
+}
+
+run()
diff --git a/web/src/utils/pixelAvatar.js b/web/src/utils/pixelAvatar.js
new file mode 100644
index 00000000..05789181
--- /dev/null
+++ b/web/src/utils/pixelAvatar.js
@@ -0,0 +1,74 @@
+const DEFAULT_SIZE = 64
+const GRID_SIZE = 5
+const MIRROR_COLUMNS = 3
+const DEFAULT_BACKGROUND = '#f3f4f6'
+
+const COLOR_PALETTE = [
+  '#265c96',
+  '#3996ae',
+  '#13c2c2',
+  '#52c41a',
+  '#faad14',
+  '#ff7a45',
+  '#ff4d4f',
+  '#9254de',
+  '#597ef7',
+  '#4f4f4f'
+]
+
+const normalizeSeed = (id) => {
+  if (id === null || id === undefined || String(id).trim() === '') {
+    throw new Error('generatePixelAvatar requires an id')
+  }
+  return String(id).trim()
+}
+
+const hashSeed = (seed) => {
+  let hash = 2166136261
+
+  for (let i = 0; i < seed.length; i += 1) {
+    hash ^= seed.charCodeAt(i)
+    hash = Math.imul(hash, 16777619)
+  }
+
+  return hash >>> 0
+}
+
+const buildCells = (hash) => {
+  const cells = []
+
+  for (let row = 0; row < GRID_SIZE; row += 1) {
+    for (let col = 0; col < MIRROR_COLUMNS; col += 1) {
+      const bitIndex = row * MIRROR_COLUMNS + col
+      const filled = ((hash >>> bitIndex) & 1) === 1
+
+      if (!filled) continue
+
+      cells.push([col, row])
+
+      const mirroredCol = GRID_SIZE - col - 1
+      if (mirroredCol !== col) {
+        cells.push([mirroredCol, row])
+      }
+    }
+  }
+
+  if (cells.length === 0) {
+    cells.push([2, 2])
+  }
+
+  return cells
+}
+
+export const generatePixelAvatar = (id) => {
+  const seed = normalizeSeed(id)
+  const hash = hashSeed(seed)
+  const color = COLOR_PALETTE[(hash >>> 16) % COLOR_PALETTE.length]
+  const cells = buildCells(hash)
+    .map(([x, y]) => `<rect x="${x}" y="${y}" width="1" height="1"/>`)
+    .join('')
+
+  const svg = `<svg xmlns="http://www.w3.org/2000/svg" width="${DEFAULT_SIZE}" height="${DEFAULT_SIZE}" viewBox="0 0 ${GRID_SIZE} ${GRID_SIZE}" shape-rendering="crispEdges"><rect width="${GRID_SIZE}" height="${GRID_SIZE}" fill="${DEFAULT_BACKGROUND}"/><g fill="${color}">${cells}</g></svg>`
+
+  return `data:image/svg+xml,${encodeURIComponent(svg)}`
+}