In order to improve the stability of the Permanent Magnet Synchronous Motor(PMSM) vector control system and reduce the hardware cost, a bipolar switch Hall sensor with high stability and low cost is used to replace the high-resolution sensor in the control system to achieve precise control of the permanent magnet synchronous motor . The article first introduces the working principle of the Hall sensor, combined with the structure of the permanent magnet synchronous motor, introduces the application of the bipolar switch Hall sensor in the motor; then analyzes the installation phase deviation of the Hall sensor, and gives the calibration of the phase deviation Method: Reuse the construction of a Hall position observer to realize the detection and estimation of the motor rotor position and speed; finally, the feasibility and superiority of the proposed Hall installation phase deviation calibration method are verified through the construction of system simulation and motor test platform experiments . The method proposed in this paper can reduce the estimation error of the rotor position of the motor to 0.33% and the estimation error of the speed within 0.5%. At the same time, the estimation stability can also be maintained under load. Improved the robustness and reliability of the permanent magnet synchronous motor control system.