Abstract: China BeiDou navigation system is in the final stage of BDS-3 construction, and its positioning accuracy has been a hot topic at home and abroad. Based on the measured data of IGS continuous tracking station, this paper expounds the Beidou triple-frequency precise point positioning model, and compares and analyzes the observation data quality of BDS-2 and BDS-3 and the positioning precision. The research found that the data quality of BDS-3 is better, compared with BDS-2. The accuracy of precise point positioning using BDS-3 satellite is slightly worse than that of BDS-2, and the convergence time is slightly slower. Combined BDS-2 and BDS-3, the precision and the convergence time of the precise point positioning is greatly improved compared with the PPP result of BDS-2 only.