1) Enable Apache on Mac OS;
2) Enable "LoadModule php5_module libxec/apache2/libphp5.so" in /private/etc/apache2/httpd.conf;
3) "sudo cp php.ini.default php.ini" in path "/private/etc", you can change the default settings of php in this file;
4) Restart apache on Mac with command "sudo apachectl restart" in terminal.