A timing advance determining method and a device are provided. In the method, a network device determines, based on a correspondence between a parameter set and a TA granularity, TA information used by a terminal on an occupied frequency domain resource, where the parameter set includes a subcarrier spacing and a cyclic prefix type of a symbol; the network device sends the TA information to the terminal; and the terminal determines, based on the correspondence between a parameter set and a TA granularity, a TA granularity corresponding to the frequency domain resource occupied by the terminal, and determines, based on the TA granularity and the TA information, a TA value used by the terminal on the occupied frequency domain resource.