This application provides a time synchronization method and an apparatus. In the method, a second communication device may indicate a synchronization accuracy configuration to a first communication device for time synchronization. In this way, as a time-receiving device, the second communication device may determine a more proper synchronization accuracy configuration meeting a synchronization accuracy requirement of the second communication device, and notify the first communication device of the synchronization accuracy configuration. According to the method, a time-providing device performs time synchronization by using the synchronization accuracy configuration.