您发布的文件有一个空格PHPExcel输出之前的字符...检查您的脚本以查看可能发送到php：//输出流的位置。检查您的初始<？php 开始标签之前是否没有空格;特别注意？> <？php 或类似的关闭/打开标签。并且还检查您的脚本中可能包含的任何文件

The file that you've posted has a single space character before the PHPExcel output... check your script to see where this might be sent to the php://output stream. Check that there's no space before your initial <?php opening tag; watch out in particular for ?> <?php or similar closing/opening tags. And also check any files that might be included by your script