A method and a device for selecting a core network device. The method includes: an access network device determining the equipment type of a user equipment (UE); when the equipment type is a machine type communication (MTC) UE, the access network device determining an MTC group identifier corresponding to the UE; when the MTC group identifier corresponds to a core network device, the access network device selecting the core network device corresponding to the MTC group identifier as a core network device which the UE accesses. In the embodiments of the present application, a plurality of MTC UE corresponding to the same MTC group identifier can select the same core network device to access a mobile communication network, and thus being able to save network resources and reduce signaling overhead using a public bearer.