Restart OCS, all ocs services can not restart, Event Log seems be full of errors related to OCS.
Then I launched  "microsift office communications server 2007 deployment wizard" , check the server settings, found "step 2 : deploy server" be marked a partial label , I click  "Run" again follow this wizard to reinstall  RTC services using  the same service Account which have been set previously. just follow and restart all OCS services, solved!