GPS carrier phase differential positioning is the direction of high precision positioning field in recent years. In the carrier phase difference solution positioning, with the increase in the length of the baseline between the user station and the base station, the unit observation vector of the satellite and the base station will have a large deviation from the unit observation vector of the satellite and the user station. As the baseline length becomes longer, the positioning error caused by the deviation becomes longer. In order to solve the above problems, a general locations’ mathematical model based on carrier phase difference algorithm is presented and the process of general positioning model is deduced, corresponding simulation results are given. The results show that the mathematical model based on the general positioning is higher than the traditional double differential positioning, and it can meet the requirement of high precision positioning.