@realcrazysun 谢谢，看到我要的了。

Streaming I/O The File I/O documented above requires that an entire workbook is built up in memory before the file can be written. While convenient, it can limit the size of the document due to the amount of memory required.

A streaming writer (or reader) processes the workbook or worksheet data as it is generated, converting it into file form as it goes. Typically this is much more efficient on memory as the final memory footprint and even intermediate memory footprints are much more compact than with the document version, especially when you consider that the row and cell objects are disposed once they are committed.