Embodiments provide a call control device, an HSS, an AS, and a user service processing method. The call control device includes: a receiving module, configured to: receive an access domain confirmation request message, comprising an identifier of the called UE, sent by a call routing device on a home network; a determining module determining, according to the identifier, that the home network communicates with a visited network of the called UE by using a CS domain on the home network; and a sending module sending an access domain confirmation response message, carrying instruction information, to the call routing device and the instruction information is used to instruct the call routing device to route the call to the visited network by using the CS domain on the home network.