An LSP establishment method and a network device, where the method includes: generating, by a first network device, a first Path message, where the first Path message carries an address of a second network device, and the first Path message is used to request establishment a first LSP; and sending, the first Path message to the second network device, and establishing the first LSP, where the first Path message further carries an address of a target network device, so that the second network device stitches the first LSP and a second LSP according to the address of the target network device, so as to form a third LSP from the first network device to the target network device. This technical solutions are conducive to implementing convergence of an access network of an IP RAN and an IP backbone network.