A path detection method and apparatus for forwarding at least two layers of labels includes generating, by a first network device, a first request packet used for path detection, where the first request packet includes a label stack and a time to live (TTL), and an initial quantity of layers of the label stack matches an initial value of the TTL, and sending the first request packet, where the first request packet instructs a second network device to send a first response packet to the first network device when the TTL is 0 after being reduced by 1, and the first response packet reaches the first network device through an internet protocol route.