The research status quo of sensor-less control scheme of permanent magnet synchronous motor is analyzed. A motor soft phase-locked loop estimation method is mentioned. In the two-phase stationary system, the mathematical model of PMSM is established to obtain the motor angle and speed information. Through the integration of back EMF information, high-pass filtering and normalized processing, the motor angle sine and cosine information are obtained. The software PLL and its key parameters are designed to get the angle and synchronous speed of PMSM. Simulation analysis and experimental results show that the soft PLL of permanent magnet synchronous motor can accurately obtain the motor angle and speed information. And the vector control system is stable and has a good dynamic characteristics based on the method. This work is supported by Science and Technology Development Plan of State Grid Corporation of China (No. SGSDDK00KJJS1500155).