A service processing method, a service processing apparatus, and a communications system are provided. The service processing method includes: receiving, by an access network device, from a core network device, a bearer setup request message of a VoLTE service; and rejecting, by the access network device, the bearer setup request message when determining that LTE network signal quality of a terminal of the VoLTE service cannot satisfy the VoLTE service. The technical solutions provided in embodiments of the present disclosure help improve stability of an established VoLTE service, thereby helping improve call experience of a user.