In order to solve the problem of GNSS position precision error increasing, this paper puts forward a kind of GNSS pseudorange measurement positioning model based on the least square method. Used the least squares method to iterate guidance solving, and adopted target position solving of five-satellites ECI coordinate system to simulate and verify. The simulation results show that location error accuracy calculated by locating model can reach 10-1 m, velocity error accuracy can reach 10-2 m/s. Final conclusion shows that the simulation results of the GNSS pseudorange measurements positioning based on the least square method, which is put forwarded in this paper, can satisfy the positioning accuracy. At the same time, we can solve the problem of positioning error increases by using the model.