<p>To enhance the control performance and anti-interference ability of permanent magnet synchronous motor, a speed control strategy that integrates integral terminal sliding mode control (ITSMC) with an internal model control (IMC) observer is proposed. ITSMC is designed by combining integral sliding mode control with terminal sliding mode control, which can effectively reduce the steady state error of the system as well as enhance its reaching speed. The sliding mode reaching law has been improved. The newly improved sliding mode reaching law can adaptively adjust its own size according to the state of the system. It shortens the system reaching time and further enhances overall control performance. The load disturbance observer is constructed based on the IMC approach. The observed load is converted into an electric current and fed forward, effectively suppressing disturbances and enhancing the system control performance and robustness. Finally, simulations and experiments were conducted on the proposed method. Analysis of the experimental results shows that, compared to traditional SMC, the improved integral terminal sliding mode control (IITSMC) reduces convergence time by 48.6% and chattering by 50%. When a load is applied, IITSMC reduces position variation by 70% and settling time by 66% compared to traditional SMC. This method enhances control performance and improves system robustness.</p>