合并 PDF
把多个 PDF 按你选择的顺序合并成一个。
这款工具完全在你的浏览器中运行。文件从不上传，你可以在浏览器的网络标签中亲自验证这一点。 亲自验证：打开浏览器的网络标签观察。你会看到一个查询你是否还有剩余任务的小请求，只包含工具名称和一段哈希，绝不会包含文件。
这款工具的作用
Merging turns several PDFs into one document. The pages are copied in the order you set, and everything on them - text, images, links, form fields - is carried across untouched. Nothing is re-encoded, so the result looks exactly like the originals and there is no loss in quality.
Reach for it when a set of files needs to travel as one: chapters of a report, a scanned contract that arrived as separate pages, an application where the form and the supporting documents must be uploaded in a single attachment, or the front and back of a document your scanner saved separately.
工作原理
- Drop your PDFs onto this page, or use the file picker. You can add more at any time.
- Drag the files into the order you want, or sort them by name or size. The number on each row is the position it will take in the finished document.
- Turn on a blank page between files if the result will be printed double-sided, so each document starts on a fresh sheet.
- Press Merge. Progress shows the page being copied, and Cancel stops it immediately.
- The download starts on its own. There is no waiting screen and no second click.
Order is the part people get wrong most often, so it is the part this tool makes most visible. Sorting by name uses natural number ordering, which means scan-2 comes before scan-10 rather than after it - the opposite of what plain alphabetical sorting does, and the reason merged scans so often arrive shuffled elsewhere.
Bookmarks are rebuilt rather than dropped. Most merge tools discard the outline because copying pages does not copy the tree that points at them; here the outline of every source is read, its destinations are re-pointed at their new page positions, and the trees are joined under one root. If a bookmark pointed at a page that was not included, its children are promoted rather than lost with it.
The file never leaves your device. The merging happens in a Web Worker inside your browser using pdf-lib, so no page of either document is ever handed to a server. You can confirm this yourself: open your browser's network tab, merge a file, and watch what goes out - one small request asking whether you have tasks left, carrying a tool name and a hash, and never the file.
There is no page limit, no daily quota and no wait between jobs. The only real constraint is your device's memory, and if a file is large enough to be a risk we say so rather than silently refusing.
常见问题
- 怎样控制页面的顺序？
- 拖放区下方的列表就是最终文档的顺序，从上到下。拖动某一行来移动它，或者用键盘时使用箭头按钮。你也可以按文件名或大小自动排序。按名称排序采用自然数字顺序，所以 page-2 会排在 page-10 之前。
- 可以合并的文件或页数有上限吗？
- 一次最多可以合并 50 个文件，页数完全没有上限。设这个上限是因为超过 50 个的列表就无法靠肉眼核对了，而不是付费墙——分两批合并效果完全一样。没有每日配额，两次任务之间也没有冷却时间。
- 我的书签和目录会保留下来吗？
- 会，只要你保持“保留书签”开启。每个文件的大纲都会被读取并重建，使每个条目仍指向合并后文档中的正确页面。目标页被排除的书签会被丢弃，但嵌套在它下面的内容会被保留并上移一级。
- 我的文件会被上传到服务器吗？
- 不会。合并完全使用 WebAssembly 在你的浏览器中进行，文件的任何部分都不会被传输。这一点可以验证，而不只是承诺：打开浏览器的开发者工具，切换到网络标签，然后合并一份文档。你不会看到任何外发请求。这款工具在断网时也能使用。
- 为什么我受密码保护的文件会失败？
- 加密的 PDF 没有密码就无法读取，因此它的页面也无法复制。请先用解锁 PDF 移除保护，再进行合并。如果文件无需密码即可打开但仍拒绝合并，那它带有所有者限制，解锁 PDF 同样可以移除。
- 合并会降低质量或让文件变大吗？
- 质量丝毫不变——页面按原样复制，文本和图像都不会重新编码。文件大小通常略小于各部分之和，因为相同的信头或嵌入字体等共享资源只存储一次，而不是重复存储。如果还需要更小，之后运行压缩 PDF。