The invention provides a method and a device for deactivating idle state signaling reduction (ISR) function. A first user mobility control and management entity of user equipment (UE) deletes data relevant to a second user mobility control and management entity in the context data which is relevant to the ISR function of the UE and saved by the first user mobility control and management entity andsends notifying message carrying the deactivating type identity to the UE so that the UE is informed of the deactivation of the ISR function thereof and is triggered to deactivate the ISR function atthe side thereof, thus the ISR function of the UE can be deactivated in an evolution grouping system.