The present invention provides a method and system for indicating data offload, and a traffic offload network element, the method comprises: when a radio bearer is established or modified, a mobility management unit of a core network notifies a traffic offload network element of the bearer type of the bearer to determine whether to start the data offload. Through the present invention, the judgment operation of the core network is simplified. In addition, under the situation that the core network side determines whether to start local access function, the traffic offload network element also can correctly start an offload policy.