diff --git a/web-to-ppt/background.js b/web-to-ppt/background.js
index 43e1600..d5f36db 100644
--- a/web-to-ppt/background.js
+++ b/web-to-ppt/background.js
@@ -171,11 +171,14 @@ chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
     return true;
   }
 
-  // 下载 PPTX（base64 data URL）
+  // 下载 PPTX（从 storage 读取 base64）
   if (message?.type === "WEB_TO_PPT_DOWNLOAD") {
     (async () => {
-      const dataUrl = 'data:application/vnd.openxmlformats-officedocument.presentationml.presentation;base64,' + message.base64;
-      await chrome.downloads.download({ url: dataUrl, filename: message.filename });
+      const stored = await chrome.storage.session.get(['pptxBase64', 'pptxFilename']);
+      if (!stored.pptxBase64) throw new Error('没有待下载的数据');
+      const dataUrl = 'data:application/vnd.openxmlformats-officedocument.presentationml.presentation;base64,' + stored.pptxBase64;
+      await chrome.downloads.download({ url: dataUrl, filename: stored.pptxFilename });
+      await chrome.storage.session.remove(['pptxBase64', 'pptxFilename']);
       return { ok: true };
     })()
       .then(sendResponse)
diff --git a/web-to-ppt/popup.js b/web-to-ppt/popup.js
index 9acc4d4..8a8737b 100644
--- a/web-to-ppt/popup.js
+++ b/web-to-ppt/popup.js
@@ -75,27 +75,24 @@ async function exportPptx() {
     setProgress(85, '正在打包...');
     const blob = await WebToPPT.schemaToPptxBlob(schema);
 
-    // 5. 下载（data URL，popup 直接调用）
-    setProgress(95, '正在下载...');
+    // 5. 转 base64
     const buffer = await blob.arrayBuffer();
     const bytes = new Uint8Array(buffer);
     let binary = '';
     for (let i = 0; i < bytes.length; i += 0x8000) {
       binary += String.fromCharCode(...bytes.subarray(i, i + 0x8000));
     }
-    const dataUrl = 'data:application/vnd.openxmlformats-officedocument.presentationml.presentation;base64,' + btoa(binary);
+    const base64 = btoa(binary);
 
+    // 6. 存到 storage，让 background 下载
+    setProgress(95, '正在下载...');
     const title = dataResult.data.source?.title || 'webpage';
     const safeTitle = title.replace(/[\\/:*?"<>|]+/g, '-').replace(/\s+/g, '-').slice(0, 64) || 'webpage';
     const filename = `web-to-ppt/${safeTitle}-${Date.now()}.pptx`;
 
-    try {
-      const dlId = await chrome.downloads.download({ url: dataUrl, filename });
-      console.log('[WebToPPT] download id:', dlId);
-    } catch (e) {
-      console.error('[WebToPPT] download error:', e.message, e);
-      throw e;
-    }
+    await chrome.storage.session.set({ pptxBase64: base64, pptxFilename: filename });
+    const dlResult = await chrome.runtime.sendMessage({ type: 'WEB_TO_PPT_DOWNLOAD' });
+    if (!dlResult || !dlResult.ok) throw new Error(dlResult?.error || '下载失败');
 
     setProgress(100, '导出完成');
     setResult('success', '导出完成');