502 keeps appearing when nginx accesses php

In the configuration too urgent, excerpt from other people's server configuration
#fastcgi_pass unix:/tmp/php-cgi.sock;
#upload filesize limit
#client_max_body_size 10m;
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
include fastcgi.conf;

Finally, it is OK to change it to your own

location ~ .*\.(php|php5)?$
{
try_files $uri =404;
fastcgi_pass unix:/tmp/php-cgi.sock;
fastcgi_index index.php;
include fcgi.conf;
}