Communication method and optical module

This application provides a communication method and an optical module. The method includes: A first optical module determines a first delay. The first optical module sends the first delay to an interface chip. According to the communication method and the optical module that are provided in this application, a delay in the optical module can be reported to the interface chip, so as to improve precision of time synchronization between a master clock and a slave clock, thereby further improving clock precision of a network device.