A method of interface registration for a network device to join in a cluster system, comprises: when the network device joins in the cluster system, the network device's local interconnection board sends its board number to the network device's local main control board, the network device's local non-interconnection board receives the board number sent by the local main control board, wherein the local interconnection board is a board on which interfaces for interconnecting the network device to network devices in the cluster system are located; after the cluster interface registration of the local non-interconnection board and local interconnection board on the cluster main control board, the local non-interconnection board and the local interconnection board receive and store a mapping relationship between local interface information of the network device and global interface information of the network device sent by the cluster main control board respectively.