Method, device and system for ensuring continuity of emergency service

A method for ensuring the continuity of emergency service is disclosed in the embodiment of the present invention. The method includes the following steps: a mobility management entity receives a handover request message or an emergency service capability judgment request message from a source base station device; the mobility management entity judges whether the target cell supports the emergency service of the user device according to the emergency service supporting capability of the network corresponding to the Tracking Area Indicator (TAI) information and/or the Routing Area Identification (RAI) information stored by the mobility management entity, the registration information of the user device, and the TAI information and/or the RAI information of the target cell; if the target cell supports the emergency service of the user device, the mobility management entity informs the source base station device or the target mobility management entity of performing a handover flow; if the target cell does not support the emergency service of the user device, the mobility management entity informs the source base station device of reselecting a target cell for the user device. The embodiment of the present invention ensures the continuity of the emergency service.