This application describes a tunnel establishment method. The method may include receiving, by a first network device, a first request message sent by a previous-hop network device, where the first request message is used to request to obtain an RSVP-TE label of the first network device, the first network device supports RSVP-TE and SR-TE, and the previous-hop network device supports RSVP-TE. The method may also include that when the first network device determines that at least one network device in downstream network devices of the first network device on a path of a to-be-established tunnel supports SR-TE, establishing an SR-TE tunnel from the first network device to a second network device, and generating a tunnel identifier used to identify the SR-TE tunnel. Furthermore, the method may include sending a first response message to the previous-hop network device, where the first response message includes the tunnel identifier.