A service redundancy method and a related apparatus, where the method includes sending, by a mobility management entity (MME), a request message to a domain name system (DNS) server, receiving a request response message sent including MME codes (MMECs) of all MMEs in the MME pool, determining a backup MME of the MME according to the MMECs of all the MMEs in the MME pool, sending an interface request message to the DNS server, where the interface request message includes an MMEC of the backup MME and the pool identity of the MME pool, receiving an interface response message from the DNS server, where the interface response message includes interface information of the backup MME, and sending, according to the interface information of the backup MME, user information of user equipment UE attached to the MME to the backup MME.