This application provides a time synchronization method, an access network device, a communication apparatus, a computer storage medium, and a communication system. The method includes: A first access network device obtains first indication information, where the first indication information is used to indicate that a first terminal has a requirement for receiving or sending an uplink time synchronization message, and/or the indication information is used to indicate a precision requirement for time synchronization between the first terminal and a wireless network. The first access network device performs time synchronization on the first terminal based on the first indication information. This can avoid a case in which a requirement on a synchronization error of a time sensitive network TSN in an uplink time synchronization scenario cannot be met due to an excessively large air interface synchronization error, so that synchronization between TSN devices is improved, and TSN performance is improved.