A method implemented by a network exposure function network element includes: sending first information of a monitoring event to a first mobility management network element; receiving identification information of a second mobility management network element from a data management network element, where the first mobility management network element supports interworking between a first network and a second network without an interface, and the first mobility management network element and the second mobility management network element respectively serve a user equipment in the first network and the second network; and sending second information of the monitoring event to the second mobility management network element based on the identification information of the second mobility management network element.