Abstract Based on the BDS-2/3 satellites observable-specific signal biases(OSB) correction product published by Wuhan University observation data of eight iGMAS stations in China for one month,we analyze the influence of OSB correction on the pseudo-distance single point positioning and precision point positioning accuracy of BDS-2/3 under the combination mode of B1I/B3I old frequency points and B1C/B2a new frequency points. The results show that the mean of B1I, B3I, B1C and B2a OSB ranged from －80 ns to 70 ns, and the annual stability of OSB at each frequency point are 3.41 ns, 5.87 ns, 2.04 ns and 2.32 ns, respectively. In terms of BDS-2/3 pseudo-range single point positioning, after using OSB product correction, the positioning accuracy of B1I/B3I combination is better than 2.53 m, the positioning accuracy of B1C/B2a combination is better than 3.84 m, and the accuracy improvement is not obvious. In terms of BDS-2/3 precise point positioning, the positioning accuracy of 3D direction using B1I/B3I is better than 7.7 cm, the improvement is about 20.6%, the convergence time is about 38 min, the improvement is about 7.3%. The positioning accuracy of 3D direction of B1C/B2a is better than 3.7 cm, and the improvement is about 11.9%. The convergence time is about 36 min, improved about 16.3%.