A PHP script uses spl_autoload_register, which runs normally under WINDOWS, but cannot be included in LINUX. Later I found that WINDOWS is not case-sensitive , and under LINUX, it is case-sensitive. Under WINDOS, spl_autoload_register will convert the class name into lower case for file search. This will cause the file to be unable to be included normally under Linux, so when naming, pay attention to the consistency of the case of the file name and the class name. .