In this paper, a shortest distance algorithm based on least squares is proposed to solve the problem of optimal intersection point when the threedimensional target is located in mobile monitoring station. The positioning model under the double mobile monitoring station is given, and the expression of the optimal intersection location is deduced. The simulation results show that the proposed method can effectively obtain the optimal intersection point which is close to the real target position, which is of great theoretical and practical significance for the multi  mobile monitoring station to locate the threedimensional target.