走了不少弯路，CentOS6 x64，去官网下载php扩展并安装(google搜)，遇到的问题见这里。

配置php.ini

;Zend Debugger
zend_extension=/usr/lib64/php/modules/ZendDebugger.so
zend_debugger.expose_remotely=always
zend_debugger.allow_hosts=192.168.136.0/24,192.168.2.0/24

参考：

http://files.zend.com/help/Zend-Studio/content/setting_your_zend_studio_for_eclipse_to_be_an_allowed_host.htm

http://files.zend.com/help/Zend-Studio/zend-studio.htm#troubleshooting_remote_debugging.htm%3FTocPath%3DUser%2520Guide%7CTasks%7CDebugging%2520Files%2520and%2520Applications%7CSetting%2520Up%2520Remote%2520Debugging%7C_____0

http://www.ibm.com/developerworks/cn/opensource/os-php-zenddebug/