Abstract: In order to improve the speed control accuracy and disturbance suppression ability of permanent magnet synchronous motors (PMSMs) under different operating conditions, this paper proposes a non-singular terminal sliding mode control method based on an extended state observer. Firstly, a mathematical model of permanent magnet synchronous motor is established, including parameter variations and load disturbances. An improved non-singular terminal sliding mode surface is designed, and a speed controller is constructed using a fast power law approach. This ensures global stability while effectively improving convergence speed and suppressing sliding mode chattering. Secondly, the introduction of an extended state observer expands the internal and external disturbances of the system into a new state variable to compensate for in the controller, significantly enhancing the system's ability to suppress disturbances. Finally, a simulation model was built in MATLAB to compare and analyze the control method proposed in this paper with the controller designed based on a linear extended state observer. The experimental results showed that the control method proposed in this paper exhibited faster convergence speed and stronger disturbance suppression ability.