A communication method and a related apparatus are disclosed. The method is performed by an MME, including: receiving an attach request message from an eNB, where the attach request message is used to request to attach to a network, and the attach request message includes an identity of the UE; sending, to an HSS according to the attach request message, an authentication data request message including the identity of the UE; receiving an authentication data response message including an AV from the HSS, where the authentication data response message is used to indicate that the authorization on the UE succeeds; and determining, according to the authentication data response message, that the UE is allowed to perform a V2X service, and performing authentication on the UE according to the AV. The method can enable a network side to perform authentication on UE during V2V communication, thereby reducing an air-interface resource overhead.