This application relates to the field of communications technologies, and provides a time synchronization method and an apparatus, to perform positioning and/or timing error measurement on a target terminal in a wireless communications system, so as to avoid a relatively large positioning error caused by a timing error between the target terminal and a base station. The method is used in a wireless positioning system, where the wireless positioning system includes a first node and a second node, and the method includes: The first node receives an arrival time t