diff --git a/src/components/Device/DeviceScreen.tsx b/src/components/Device/DeviceScreen.tsx
index e2bf319..8cad483 100644
--- a/src/components/Device/DeviceScreen.tsx
+++ b/src/components/Device/DeviceScreen.tsx
@@ -38,10 +38,13 @@ const DeviceScreen: React.FC<DeviceScreenProps> = ({ deviceId, onScreenSizeChang
   const isRenderingRef = useRef(false)
   const imageSizeRef = useRef<{ width: number, height: number } | null>(null)
   
-  // canvas锁定尺寸：首次有效帧确定canvas尺寸后不再变化，
+  // canvas锁定尺寸：取历史最大帧尺寸锁定，
   // 避免不同采集模式(MediaProjection/无障碍截图)帧尺寸不一致导致闪烁
   const lockedCanvasSizeRef = useRef<{ width: number, height: number } | null>(null)
   
+  // Base64预解码缓存：将base64字符串提前转为Blob，避免渲染时阻塞主线程
+  const pendingBlobRef = useRef<Blob | null>(null)
+  
   // 添加控制权状态跟踪，避免重复申请
   const [isControlRequested, setIsControlRequested] = useState(false)
   const [currentWebSocket, setCurrentWebSocket] = useState<any>(null)
@@ -147,17 +150,43 @@ const DeviceScreen: React.FC<DeviceScreenProps> = ({ deviceId, onScreenSizeChang
           console.log(`[屏幕数据] 已收到 ${frameCountRef.current} 帧, 数据大小: ${dataLen}, 渲染中: ${isRenderingRef.current}, 解码中: ${decodingRef.current}`)
         }
         
-        // 只保存最新帧引用，不立即解码
-        latestFrameRef.current = data
+        // 提前将Base64转为Blob，避免渲染循环中阻塞主线程
+        // fetch+data URI方式比atob+逐字节复制快得多，且不阻塞主线程
+        const format = data?.format ?? 'JPEG'
+        const mimeType = `image/${format.toLowerCase()}`
+        
+        if (typeof data.data === 'string') {
+          try {
+            const dataUri = `data:${mimeType};base64,${data.data}`
+            fetch(dataUri)
+              .then(res => res.blob())
+              .then(blob => {
+                pendingBlobRef.current = blob
+                latestFrameRef.current = data
+                
+                if (!isRenderingRef.current) {
+                  isRenderingRef.current = true
+                  renderLatestFrame()
+                }
+              })
+              .catch(err => {
+                console.error('Base64 pre-decode failed:', err)
+              })
+          } catch (err) {
+            console.error('Frame pre-decode error:', err)
+          }
+        } else {
+          pendingBlobRef.current = new Blob([data.data], { type: mimeType })
+          latestFrameRef.current = data
+          
+          if (!isRenderingRef.current) {
+            isRenderingRef.current = true
+            renderLatestFrame()
+          }
+        }
         
         // 只在首帧时更新loading状态，避免每帧触发重渲染
         if (isLoading) setIsLoading(false)
-        
-        // 如果没有正在进行的渲染循环，启动一个
-        if (!isRenderingRef.current) {
-          isRenderingRef.current = true
-          renderLatestFrame()
-        }
       }
     }
 
@@ -293,14 +322,16 @@ const DeviceScreen: React.FC<DeviceScreenProps> = ({ deviceId, onScreenSizeChang
   const renderLatestFrame = useCallback(() => {
     const doRender = () => {
       const frameData = latestFrameRef.current
-      if (!frameData) {
+      const preDecodedBlob = pendingBlobRef.current
+      if (!frameData || !preDecodedBlob) {
         // 没有新帧，停止循环，等 handleScreenData 重新启动
         isRenderingRef.current = false
         return
       }
 
-      // 取走帧数据
+      // 取走帧数据和预解码Blob
       latestFrameRef.current = null
+      pendingBlobRef.current = null
 
       const canvas = canvasRef.current
       if (!canvas) {
@@ -316,27 +347,15 @@ const DeviceScreen: React.FC<DeviceScreenProps> = ({ deviceId, onScreenSizeChang
       // 上一帧还在解码，把数据放回去，下个 rAF 再试
       if (decodingRef.current) {
         latestFrameRef.current = frameData
+        pendingBlobRef.current = preDecodedBlob
         rafIdRef.current = requestAnimationFrame(doRender)
         return
       }
 
       decodingRef.current = true
 
-      let blobPromise: Promise<Blob>
-      if (typeof frameData.data === 'string') {
-        const binaryStr = atob(frameData.data)
-        const len = binaryStr.length
-        const bytes = new Uint8Array(len)
-        for (let i = 0; i < len; i++) {
-          bytes[i] = binaryStr.charCodeAt(i)
-        }
-        blobPromise = Promise.resolve(new Blob([bytes], { type: `image/${frameData.format.toLowerCase()}` }))
-      } else {
-        blobPromise = Promise.resolve(new Blob([frameData.data], { type: `image/${frameData.format.toLowerCase()}` }))
-      }
-
-      blobPromise
-        .then(blob => createImageBitmap(blob))
+      // 直接使用预解码的Blob，跳过Base64解码步骤
+      createImageBitmap(preDecodedBlob)
         .then(bitmap => {
           decodingRef.current = false
 
@@ -347,23 +366,32 @@ const DeviceScreen: React.FC<DeviceScreenProps> = ({ deviceId, onScreenSizeChang
             return
           }
 
-          // canvas尺寸锁定策略：
-          // 首次有效帧确定canvas尺寸后锁定，后续帧直接绘制到固定尺寸canvas上
-          // 避免不同采集模式帧尺寸不一致导致canvas反复resize闪烁
+          // canvas尺寸锁定策略（增强版）：
+          // 取历史最大帧尺寸锁定canvas，避免小帧导致画面缩小闪烁
+          // 当新帧比锁定尺寸大时，更新锁定尺寸（设备旋转等场景）
           const locked = lockedCanvasSizeRef.current
           if (!locked) {
             // 首次帧：锁定canvas尺寸
             lockedCanvasSizeRef.current = { width: bitmap.width, height: bitmap.height }
             canvas.width = bitmap.width
             canvas.height = bitmap.height
-          } else if (canvas.width !== locked.width || canvas.height !== locked.height) {
-            // canvas被外部重置了，恢复锁定尺寸
-            canvas.width = locked.width
-            canvas.height = locked.height
+          } else {
+            // 后续帧：只在新帧更大时更新锁定尺寸，防止缩小闪烁
+            const needUpdate = bitmap.width > locked.width || bitmap.height > locked.height
+            if (needUpdate) {
+              const newW = Math.max(locked.width, bitmap.width)
+              const newH = Math.max(locked.height, bitmap.height)
+              lockedCanvasSizeRef.current = { width: newW, height: newH }
+              canvas.width = newW
+              canvas.height = newH
+            } else if (canvas.width !== locked.width || canvas.height !== locked.height) {
+              // canvas被外部重置了，恢复锁定尺寸
+              canvas.width = locked.width
+              canvas.height = locked.height
+            }
           }
 
           // 始终将bitmap绘制到整个canvas区域，浏览器自动缩放
-          // 这样不同尺寸的帧都能正确显示，不会闪烁
           ctx.drawImage(bitmap, 0, 0, canvas.width, canvas.height)
 
           // 使用锁定的canvas尺寸上报，保持稳定
@@ -392,7 +420,7 @@ const DeviceScreen: React.FC<DeviceScreenProps> = ({ deviceId, onScreenSizeChang
         })
         .catch(err => {
           decodingRef.current = false
-          console.error('图像解码失败:', err)
+          console.error('Image decode failed:', err)
           rafIdRef.current = requestAnimationFrame(doRender)
         })
     }