A method for switching route and a network device are disclosed, wherein the method comprises: setting a relationship between a port number of each destination port and a port number of the transmitting port, the port number of each transmitting port is the port number of the corresponding destination port; when there is a service failure in any destination port, modifying the port number of the transmitting port corresponding to a fault destination port into the port number of the backup port corresponding to the fault destination port in the set relationship, and saving the modified relationship; after receiving a data packet, the network device transmitting the data packet based on the saved relationship. The network device comprises a CPU, a first routing unit and a second routing unit. In accordance with the present invention, the time consumed by modifying routing data can be reduced, enabling the network device to switch route quickly and the user services to recover quickly.