Abstract: In order to improve the disturbance rejection performance and speed tracking dynamic performance of permanent magnet synchronous motor (PMSM), a PMSM speed control strategy based on extended state observer compound control and improved sliding mode control law was proposed. Firstly, a compound observer of linear extended state observer and nonlinear extended state observer is designed. The linear extended state observer ensures the robust stability of the system under strong disturbance, and the nonlinear extended state observer improves the estimation accuracy of high-frequency disturbance and small deviation through an adaptive nonlinear gain mechanism, thus integrating the advantages of linear and nonlinear observers. Secondly, feedforward control combines linear error feedback with improved sliding mode control law, and by introducing saturation function, the chattering phenomenon of traditional sliding mode control is weakened, while retaining its fast response characteristics. Finally, the simulations and experiments show that the compound control strategy proposed in this paper improves the performance of PMSM in dynamic response speed and anti-interference ability.