In this paper, a method of multipoint location is raised based on the passive detection system and the mathematic model and error model is set up used to measure position. Analyzing a detection system relationship of minimal location fuzziness area and range, relationship of location space error, bearing angle and relationship of circular probable error of multipoint location and range and giving the simulation curve. From the result of the simulation, the location precision of this passive detection system is high. But which should be paid attention to is that the aero error and some other system error are not in the error model, in fact, those errors have a great effect on the location precision of this passive detection system. By corrections, the system error can be reduced, but which can't be removed completely.