Embodiments of the invention relate to communications field, in particular, to a downlink data notification message sending method, and apparatus. The method is: receiving, a delay instruction sent by a mobility management network element, which is used to instruct a control plane network element to delay sending a DDN message; receiving, an event report message sent by a user plane network element, where the event report message includes a reported event, and the reported event is used to notify the control plane network element that a downlink data packet sent to UE matches no bearer; determining, that the UE is registered in the mobility management network element; and if the control plane network element has not received, within a first time period, routing information of a base station, sending, the DDN message to the mobility management network element when the first time period expires.