1. A service processing method, comprising:receiving, by an access network device, from a core network device, a bearer setup request message of a voice over long term evolution (VoLTE) service;
determining, by the access network device, that the terminal is in a weak coverage area of the access network device;
sending, by the access network device through the core network device, a radio resource not available indication to an interne protocol multimedia subsystem (IMS);
sending, by the IMS according to the radio resource not available indication, a message which triggers the terminal to initiate a circuit switched fallback call to the terminal; and
canceling, by the IMS according to the radio resource not available indication, the VoLTE service of the terminal.