I try service pagespeed stop But, I couldn't stop How can I stop the service ?
It's not a service, ngx_pagespeed is an Nginx module compiled into Nginx web server and is disabled by default. Unless you specifically enable it. See ngx_pagespeed install. If you want to remove ngx_pagespeed completely from Nginx see ngx_pagespeed install on Centmin Mod - Menu based Nginx installer for CentOS servers