你的 PHP 配置不正确。请 Google「nginx php fastcgi」。

另外附上我自用的 nginx PHP 配置：

index    index.php index.html;
location ~ (.+\.php\d?)($|/) {
        fastcgi_pass    unix:/run/php-fpm/php-fpm.sock;
        fastcgi_index    index.php;
        set    $script    $request_filename;
        if ($request_filename ~ ^(.+\.php\d?)(/.*)$){
                set $script    $1;
                set $pathinfo    $2;
        }
        fastcgi_param    PATH_INFO    $pathinfo if_not_empty;
        fastcgi_param    SCRIPT_FILENAME    $script;
        include        fastcgi_params;
}