Aiming at the problem that the permanent magnet synchronous motor vector control system is susceptible to motor parameter changes and load disturbances, a non singular fast terminal sliding mode control strategy based on load observation is proposed. A non singular fast terminal sliding mode speed controller is designed to replace the traditional PI regulator, which improves the system robustness. At the same time, a load torque observer is introduced to observe the load in real time, and the observed value is used as current feedforward compensation to improve the system anti load-disturbance ability. Simulation results show that compared with PI control, the proposed control strategy has a faster response speed，and has strong robustness to load disturbances.