diff --git a/frontend/src/components/meeting/MeetingToolbar.vue b/frontend/src/components/meeting/MeetingToolbar.vue
index f31ce1b..151879d 100644
--- a/frontend/src/components/meeting/MeetingToolbar.vue
+++ b/frontend/src/components/meeting/MeetingToolbar.vue
@@ -49,6 +49,7 @@
     </button>
 
     <button
+      v-if="!replaceChatWithScreenShare"
       class="btn btn-screen"
       :class="{ active: screenSharing, loading: screenLoading }"
       :disabled="screenLoading || screenDisabled"
@@ -127,7 +128,36 @@
       <text class="label">成员</text>
     </button>
 
-    <button class="btn" :disabled="!allowChat" @click="emitIf('chat')">
+    <button
+      v-if="replaceChatWithScreenShare"
+      class="btn btn-screen-share-slot"
+      :class="{ active: screenSharing, loading: screenLoading }"
+      :disabled="screenLoading || screenDisabled"
+      :title="screenDisabledReason || ''"
+      @click="emitIf('screen-toggle')"
+    >
+      <view class="icon">
+        <svg v-if="screenSharing" viewBox="0 0 24 24" width="22" height="22" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+          <rect x="2" y="3" width="20" height="14" rx="2" ry="2"></rect>
+          <line x1="8" y1="21" x2="16" y2="21"></line>
+          <line x1="12" y1="17" x2="12" y2="21"></line>
+          <line x1="6" y1="7" x2="18" y2="13"></line>
+          <line x1="18" y1="7" x2="6" y2="13"></line>
+        </svg>
+        <svg v-else viewBox="0 0 24 24" width="22" height="22" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+          <rect x="2" y="3" width="20" height="14" rx="2" ry="2"></rect>
+          <line x1="8" y1="21" x2="16" y2="21"></line>
+          <line x1="12" y1="17" x2="12" y2="21"></line>
+          <polyline points="9 10 12 7 15 10"></polyline>
+          <line x1="12" y1="7" x2="12" y2="14"></line>
+        </svg>
+      </view>
+      <text class="label">
+        <text class="label-desktop">{{ screenSharing ? '停止共享' : '共享屏幕' }}</text>
+        <text class="label-mobile">{{ screenSharing ? '停止' : '共享' }}</text>
+      </text>
+    </button>
+    <button v-else class="btn" :disabled="!allowChat" @click="emitIf('chat')">
       <view class="icon">
         <svg viewBox="0 0 24 24" width="22" height="22" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
           <path d="M21 15a2 2 0 0 1-2 2H7l-4 4V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2z"></path>
@@ -173,7 +203,9 @@ const props = defineProps({
   /** Phase B 录制：当前是否在录制中 */
   recording: { type: Boolean, default: false },
   /** Phase B 录制：REST 调用 / 上传中 loading 态，禁用按钮 */
-  recordingLoading: { type: Boolean, default: false }
+  recordingLoading: { type: Boolean, default: false },
+  /** 云律律师端：用「共享屏幕」替换「聊天」按钮（移动端工具栏不隐藏屏幕共享） */
+  replaceChatWithScreenShare: { type: Boolean, default: false }
 })
 
 const emit = defineEmits(['mic-toggle', 'cam-toggle', 'screen-toggle', 'recording-toggle', 'invite', 'members', 'chat', 'leave'])
@@ -336,6 +368,10 @@ const emitIf = (name) => {
   .btn-screen {
     display: none;
   }
+  /* 律师端：共享屏幕占原「聊天」槽位，移动端仍需显示 */
+  .btn-screen-share-slot {
+    display: flex;
+  }
   .icon {
     width: 64rpx;
     height: 64rpx;
diff --git a/frontend/src/pages/cloud-law/video-call.vue b/frontend/src/pages/cloud-law/video-call.vue
index e8964f9..4e7f3ed 100644
--- a/frontend/src/pages/cloud-law/video-call.vue
+++ b/frontend/src/pages/cloud-law/video-call.vue
@@ -96,7 +96,17 @@
         </view>
 
         <view class="controls-row controls-row-bottom">
-          <view class="control-item" @click="takeSnapshot" @tap="takeSnapshot">
+          <!-- 律师端：底部左侧为共享屏幕（替代通用会议页「聊天」能力） -->
+          <view v-if="isLawRole" class="control-item" @click="onScreenToggle" @tap="onScreenToggle">
+            <view
+              class="control-btn dark-btn text-icon-btn"
+              :class="{ active: screenSharingByMe, loading: screenLoading, disabled: screenDisabled && !screenSharingByMe }"
+            >
+              <text class="text-icon">{{ screenSharingByMe ? '停' : '屏' }}</text>
+            </view>
+            <text class="control-label">{{ screenSharingByMe ? '停止共享' : '共享屏幕' }}</text>
+          </view>
+          <view v-else class="control-item" @click="takeSnapshot" @tap="takeSnapshot">
             <view class="control-btn dark-btn text-icon-btn">
               <image v-if="!captureIconError" class="control-image" :src="captureIcon" mode="aspectFit" @error="captureIconError = true"></image>
               <text v-else class="text-icon">截</text>
@@ -177,6 +187,7 @@ const joining = ref(false)
 const joinError = ref('')
 const audioLoading = ref(false)
 const videoLoading = ref(false)
+const screenLoading = ref(false)
 const leaving = ref(false)
 const startedAt = ref(0)
 const nowTs = ref(Date.now())
@@ -244,7 +255,56 @@ const participants = computed(() => {
 
 const localTrackVersion = computed(() => {
   const producers = meetingStore.localProducers || {}
-  return `${producers.audio || ''}-${producers.video || ''}`
+  return `${producers.audio || ''}-${producers.video || ''}-${producers.screen || ''}`
+})
+
+const screenSharingActive = computed(() => !!meetingStore.screenShare?.ownerUserId)
+const screenSharingByMe = computed(() => {
+  const owner = meetingStore.screenShare?.ownerUserId
+  return !!owner && sameUser(owner, myUserId.value)
+})
+const screenSupported = computed(() => {
+  // #ifdef H5
+  return typeof navigator !== 'undefined' &&
+    !!navigator.mediaDevices &&
+    typeof navigator.mediaDevices.getDisplayMedia === 'function'
+  // #endif
+  // #ifndef H5
+  return false
+  // #endif
+})
+const screenDisabled = computed(() => {
+  if (!screenSupported.value) return true
+  if (screenSharingActive.value && !screenSharingByMe.value) return true
+  return false
+})
+const screenDisabledReason = computed(() => {
+  if (!screenSupported.value) return '当前环境不支持屏幕共享'
+  if (screenSharingActive.value && !screenSharingByMe.value) return '已有成员正在共享屏幕'
+  return ''
+})
+
+const screenTile = computed(() => {
+  const owner = meetingStore.screenShare?.ownerUserId
+  if (!owner) return null
+  localTrackVersion.value
+  remoteTrackVersion.value
+  const isLocal = sameUser(owner, myUserId.value)
+  const track = isLocal
+    ? meetingStore.getLocalTrack('screen')
+    : meetingStore.getRemoteTrack(owner, 'screen')
+  if (!track) return null
+  return {
+    key: `screen_${owner}`,
+    userId: owner,
+    name: isLocal ? '你' : nameOf(owner),
+    isLocal,
+    isHost: sameUser(owner, hostId.value),
+    audioEnabled: false,
+    videoEnabled: true,
+    audioTrack: null,
+    videoTrack: track
+  }
 })
 
 const remoteTrackVersion = computed(() => {
@@ -252,7 +312,7 @@ const remoteTrackVersion = computed(() => {
   const map = meetingStore.remoteConsumers || {}
   Object.keys(map).forEach(uid => {
     const slot = map[uid]
-    parts.push(`${uid}:${slot?.audio?.id || ''}:${slot?.video?.id || ''}`)
+    parts.push(`${uid}:${slot?.audio?.id || ''}:${slot?.video?.id || ''}:${slot?.screen?.id || ''}`)
   })
   return parts.join('|')
 })
@@ -315,6 +375,7 @@ const tiles = computed(() => {
 const selfTile = computed(() => tiles.value.find(t => t.isLocal) || null)
 const remoteTile = computed(() => tiles.value.find(t => !t.isLocal && t.videoTrack) || tiles.value.find(t => !t.isLocal) || null)
 const primaryTile = computed(() => {
+  if (screenTile.value) return screenTile.value
   if (preferSelfMain.value && selfTile.value) return selfTile.value
   return remoteTile.value || selfTile.value
 })
@@ -650,6 +711,28 @@ const flipCamera = () => {
   flipCameraByCommand()
 }
 
+const onScreenToggle = async () => {
+  if (screenLoading.value) return
+  if (screenDisabled.value && !screenSharingByMe.value) {
+    uni.showToast({ title: screenDisabledReason.value || '无法共享屏幕', icon: 'none' })
+    return
+  }
+  screenLoading.value = true
+  try {
+    if (screenSharingByMe.value) {
+      await meetingStore.stopScreenShare()
+    } else {
+      await meetingStore.startScreenShare()
+    }
+  } catch (err) {
+    if (err?.name !== 'NotAllowedError') {
+      uni.showToast({ title: err?.message || '屏幕共享失败', icon: 'none' })
+    }
+  } finally {
+    screenLoading.value = false
+  }
+}
+
 const executeCloudLawCommand = async (cmd = {}) => {
   const command = String(cmd.command || cmd.type || '').toLowerCase()
   const value = cmd.value
@@ -893,6 +976,13 @@ onLoad(query => {
   cloudLawApiBase.value = query?.cloudLawApiBase || query?.cloud_law_api_base || ''
   cloudLawToken.value = query?.cloudLawToken || query?.cloud_law_token || ''
   cloudLawRole.value = query?.cloudLawRole || query?.cloud_law_role || ''
+  // #ifdef H5
+  if (String(cloudLawRole.value).toLowerCase() === 'law') {
+    try {
+      window.sessionStorage.setItem('echo_cloud_law_meeting_role', 'law')
+    } catch (e) {}
+  }
+  // #endif
   const mode = String(query?.mode || query?.callType || query?.type || '').toLowerCase()
   callMode.value = mode === 'voice' || mode === 'audio' ? 'voice' : 'video'
   joinMeeting()
@@ -1233,6 +1323,10 @@ onUnload(() => {
 .control-btn.disabled {
   opacity: 0.94;
 }
+.control-btn.active {
+  background: linear-gradient(180deg, #4f8dff, #2563eb);
+  border-color: rgba(79, 141, 255, 0.55);
+}
 .hangup-btn {
   width: 150rpx;
   height: 150rpx;
diff --git a/frontend/src/pages/meeting/preview.vue b/frontend/src/pages/meeting/preview.vue
index 28adae7..f49d5bb 100644
--- a/frontend/src/pages/meeting/preview.vue
+++ b/frontend/src/pages/meeting/preview.vue
@@ -123,6 +123,7 @@ const mode = ref('create')
 const joinCode = ref('')
 const joinPassword = ref('')
 const autoJoin = ref(false)
+const cloudLawRole = ref('')
 const initializing = ref(true)
 // autoJoin 失败/超时的可见错误（替代无限"正在进入会议…"转圈）
 const autoJoinError = ref('')
@@ -467,7 +468,8 @@ const onJoin = async (options = {}) => {
       await meetingStore.joinAndEnter(joinCode.value, joinPassword.value, prefs)
     }
     const roomCode = meetingStore.currentRoom?.room_code
-    uni.redirectTo({ url: `/pages/meeting/room${roomCode ? `?code=${roomCode}` : ''}` })
+    const roleQ = cloudLawRole.value ? `&cloudLawRole=${encodeURIComponent(cloudLawRole.value)}` : ''
+    uni.redirectTo({ url: `/pages/meeting/room${roomCode ? `?code=${roomCode}${roleQ}` : (roleQ ? `?${roleQ.slice(1)}` : '')}` })
   } catch (err) {
     const msg = err?.message || JSON.stringify(err)
     // autoJoin 模式下把错误显式呈现在页面（toast 一闪而过，真机很难看清）
@@ -491,7 +493,15 @@ onLoad(async (query) => {
   try {
     mode.value = query?.mode === 'join' ? 'join' : 'create'
     joinCode.value = query?.code || ''
+    cloudLawRole.value = query?.cloudLawRole || query?.cloud_law_role || ''
     autoJoin.value = query?.autoJoin === '1' || query?.autoJoin === 'true' || query?.autoJoin === true
+    // #ifdef H5
+    if (String(cloudLawRole.value).toLowerCase() === 'law') {
+      try {
+        window.sessionStorage.setItem('echo_cloud_law_meeting_role', 'law')
+      } catch (e) {}
+    }
+    // #endif
     console.log('[Preview] onLoad params:', {
       query,
       mode: mode.value,
diff --git a/frontend/src/pages/meeting/room.vue b/frontend/src/pages/meeting/room.vue
index 4339242..908ac16 100644
--- a/frontend/src/pages/meeting/room.vue
+++ b/frontend/src/pages/meeting/room.vue
@@ -145,6 +145,7 @@
       :show-recording="isHost"
       :recording="isRecording"
       :recording-loading="recordingLoading"
+      :replace-chat-with-screen-share="replaceChatWithScreenShare"
       @mic-toggle="onMicToggle"
       @cam-toggle="onCamToggle"
       @screen-toggle="onScreenToggle"
@@ -230,6 +231,10 @@ import SelfVideoFloat from '@/components/meeting/SelfVideoFloat.vue'
 const meetingStore = useMeetingStore()
 const userStore = useUserStore()
 
+/** 云律律师端：工具栏用共享屏幕替换聊天 */
+const cloudLawRole = ref('')
+const replaceChatWithScreenShare = computed(() => String(cloudLawRole.value).toLowerCase() === 'law')
+
 const memberVisible = ref(false)
 const inviteVisible = ref(false)
 const chatVisible = ref(false)
@@ -839,6 +844,14 @@ let stateStopWatch = null
 let redirectingToJoin = false
 
 onLoad((query) => {
+  cloudLawRole.value = query?.cloudLawRole || query?.cloud_law_role || ''
+  if (!cloudLawRole.value) {
+    // #ifdef H5
+    try {
+      cloudLawRole.value = window.sessionStorage.getItem('echo_cloud_law_meeting_role') || ''
+    } catch (e) {}
+    // #endif
+  }
   // 刷新页面 / 直链访问 room 时 store 为空，回跳 join 避免白屏
   if (!meetingStore.isInMeeting) {
     const paramCode = (query?.code || '').replace(/\D/g, '')