Embodiments of the present disclosure disclose a registration area determining method, to reduce overheads for sending paging signaling to user equipment. The method in the embodiments of the present disclosure includes: determining, by a mobility management entity, that both duration in which user equipment does not access a basic registration area in a registration area of the user equipment and duration in which the user equipment does not initiate a periodic basic registration area update procedure are greater than or equal to preset duration; generating, by the mobility management entity, a new registration area for the user equipment, where the new registration area does not include the basic registration area; and sending, by the mobility management entity, the new registration area to the user equipment. The embodiments of the present disclosure further provide a mobility management entity, to reduce the overheads for sending paging signaling to the user equipment.