Method, communication system for resource processing and mobile management network element

The invention discloses a resource processing method, a communication system and a mobile management network element. A resource processing method comprises the following steps: in the process that user equipment UE is switched from a packet domain network to a circuit switched domain network, after the mobile management network element of the packet domain network receives release request messages sent by the access network of the packet domain network or switching completion messages sent by the circuit switched domain network, the resources of UE in the packet domain network are processed, thereby realizing the processing of the resources of UE in the packet domain network in the switching process of UE from the packet domain network to the circuit switched domain network. The invention also discloses a communication system and a mobile management network element.