nginx 默认不支持PATH_INFO
那么不能正常使用CI。
更改nginx.conf 配置

server {
    listen      80;
    server_name localhost;
    index       index.php index.html index.htm;
    root        /Users/renfrank/Sites/;
  location ~ \.php{
   fastcgi_pass 127.0.0.1:9000;
       fastcgi_index index.php;
        ##########################################pathinfo 模式
        set $path_info "";
        set $real_script_name $fastcgi_script_name;
        if ($fastcgi_script_name ~ "^(.+?\.php)(/.+)$"){
             set $real_script_name $1;
             set $path_info $2;
        }
        include fastcgi.conf;
        fastcgi_param SCRIPT_FILENAME $document_root$real_script_name;
        fastcgi_param SCRIPT_NAME $real_script_name;
        fastcgi_param PATH_INFO $path_info;
        ##########################################nginx支持pathinfo 模式的重点    

   }

}

同时CI 中 config.php

$config[‘base_url‘] = ‘‘;
    $config[‘index_page‘] = ‘index.php‘;
    $config[‘uri_protocol‘] = ‘PATH_INFO‘;