This application discloses a method and apparatus for implementing entry backup. When a first network device needs to back up information about a first entry stored in the first network device to a second network device, the first network device generates a first BGP message that includes first entry information, and sends the first BGP message to the second network device, where the first BGP message is used to advertise a newly defined entry backup route to the second network device, or the first BGP message includes an extended community attribute. After receiving the first BGP message, the second network device may obtain a second entry based on the first BGP message, and store information about the second entry, where the second entry is a backup entry of the first entry.