查找以下选项并修改-> 
file_uploads = On ;打开文件上传选项 
upload_max_filesize = 500M ;上传文件上限 


如果要上传比较大的文件，仅仅以上两条还不够，必须把服务器缓存上限调大，把脚本最大执行时间变长 
post_max_size = 500M ;post上限 
max_execution_time = 1800 ; Maximum execution time of each script, in seconds脚本最大执行时间 
max_input_time = 1800 ; Maximum amount of time each script may spend parsing request data 
memory_limit = 128M ; Maximum amount of memory a script may consume (128MB)内存上限

php修改上传文件大小