According to the demand for high accuracy navigation, this paper analyzes difference positioning method, and builds the model of pseudo difference and carrier phase difference. Then set up the BDS testing platform. The positioning accuracy of difference is verified through the moving vehicle test. The results indicate that the accuracy of pseudo difference positioning is prior to 2 m (2σ), and carrier phase difference prior to 0.04 m (2σ), Carrier phase difference can satisfy the demand of high accuracy navigation, it has great engineering application value.