根据hostloc上的高手指点后我已经将代码简化到极致了！ nginx的try_files功能非常强大，可以判断文件是否存在！ 通过try_files判断 当文件不存在就跳到@backend块上处理，这样伪静态的url就轻松搞定了！

location ~ .*\.(php|jsp|cgi|pl|py|php4|php5)?\$ {
include proxy.inc;
}
location / {
try_files \$uri @backend;
}
location @backend {
internal;
include proxy.inc;
}
location ~ .*\.(ftpquota|htaccess|htpasswd|asp|aspx|jsp|asa|mdb)?\$ {
deny all;

#proxy.inc 内容代码
proxy_connect_timeout 30s;
proxy_send_timeout   90;
proxy_read_timeout   90;
proxy_buffer_size    32k;
proxy_buffers     4 32k;
proxy_busy_buffers_size 64k;
proxy_pass http://127.0.0.1:81;
proxy_redirect     off;
proxy_hide_header  Vary;
proxy_set_header   Accept-Encoding '';
proxy_ignore_headers Set-Cookie Cache-Control Expires;
proxy_set_header   Host   $host;
proxy_set_header   Referer $http_referer;
proxy_set_header   Cookie $http_cookie;
proxy_set_header   X-Real-IP  $remote_addr;
proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
client_max_body_size 100m;
client_body_buffer_size 128k;