Disclosed are a packet forwarding method, a device, and a system. The method includes: A first network device receives a first message sent by a second network device via a second egress port of the second network device, where the first message is used to measure a phase difference, and the phase difference is a phase difference between a switching time of one of a plurality of first buffers of a first egress port of the first network device and a switching time of one of a plurality of second buffers of the second egress port of the second network device with a link delay taken into consideration; the first network device determines the phase difference based on the first message; and then the first network device schedules, based on the phase difference, a second data packet sent via the first egress port. In this way, the first network device and the second network device implement queuing and forwarding of data packets without time synchronization.