Abstract: The several methods of determining the orbit of geostationary satellites using GPS are summarized.The calculation demonstration is carried out according to the method of determining the orbit of geostationary satellites which only receive the signals transmitted by the GPS constellations.The availability of GPS for geostationary satellite in one period of 24 hours is obtained after computation,and the availability under different conditions is discussed.Upon analyzing the availability of GPS,a method is proposed to determine the orbit of geostationary satellites using GPS.