A service continuity ensuring method, a control plane gateway, and a mobility management network element, where the method includes: receiving, by a control plane gateway (C-GW), current location information of a user equipment (UE) sent by a mobility management network element; selecting, by the C-GW, at least one forwarding distributed gateway (D-GW) for the UE according to the current location information of the UE; and establishing, by the C-GW for the UE, a data forwarding tunnel between a source D-GW of the UE and the forwarding D-GW, and a data forwarding tunnel between the forwarding D-GW and a target base station of the UE, where the data forwarding tunnels are used to transmit uplink user plane data and/or downlink user plane data of the UE in a moving process of the UE.