Method, device and system for updating wireless capability

The embodiment of the invention discloses a method for updating a wireless capability, which comprises the following steps of: informing a mobile management entity (MME) that the GERAN/UTRAN capability of user equipment (UE) changes according to a non access layer (NAS) message sent by the UE which is in a connection state, initiating a process for inquiring the wireless capability of the UE according to an instruction for inquiring a user capability sent by the MME, and forwarding a wireless capability message sent by the UE to the MME so that the UE which is in the connection state can timely inform the MME to acquire a new wireless capability of the UE when the GERAN/UTRAN capability of the UE which is in the connection state changes and avoid a failure for Inter-RAT switching. The invention also provides a device for updating the wireless capability.