Abstract: Generally,it is impossible to determine the 3 dimensions location of a moving body only by two TDRS's tracking distance data.In order to do this work,some accessory information must be given.In this paper,six kinds of condition are summarized and a series of locating algorithms are constructed,based on the theoretical trajectory of rocket .The influence of tracking error and the bias of the theoretical trajectory departure is discussed,also.At the end of this paper,some simulation is done.The simulation results show that these location algorithms given in this paper is efficient.