Abstract: Embodiments of the present invention disclose a method and an apparatus for authenticating a communication device, where the method includes: receiving an attach request including a group identifier and sent by an MTC device to be authenticated, where the group identifier is a group identifier of an MTC group where the MTC device to be authenticated is located; determining whether a first group authentication vector bound to the group identifier exists locally, where the first group authentication vector is an authentication vector used for authenticating MTC devices in the MTC group; and if existing, according to the first group authentication vector, authenticating the MTC device to be authenticated, and generating a system key of the MTC device to be authenticated. The technical solutions provided in the present invention can be applied to the technical field of authenticating the MTC device.