Abstract: Aiming at the problem that trilateration positioning algorithm based on weighted least squares (WLS) lost positioning information in linearization process, an improved trilateration positioning algorithm was proposed. In the algorithm, WLS algorithm is used to roughly estimate coordinates of unknown nodes, and lost positioning information is used to construct positioning model, so precise positioning is achieved by solving the positioning model. The simulation results show that positioning accuracy of the proposed algorithm is obviously higher than that of the trilateration positioning algorithm based on WLS, and the larger the length-width ratio of roadway is, the better the positioning performance of the proposed algorithm is.