Example methods and apparatus for determining a timing advance are described. One example method includes obtaining ephemeris information of a satellite, where the ephemeris information includes coordinates of the satellite and an ephemeris error of the satellite. A timing advance is determined according to a preset rule based on the ephemeris information and location information of a terminal device, where the location information includes coordinates of the terminal device and a positioning error of the terminal device. The preset rule is determined by using a first horizontal distance, a first vertical distance, the ephemeris error, and the positioning error.