Abstract: In the process of asynchronous motor vector control, the motor speed information is obtained through the speed measuring devices. Influenced by such factors as interference, quantization errors, and motor operating conditions, the detection elements gives the speed information mixed with noise that needs to be filtered, but the traditional speed filtering method cannot consider both real-time and precision requirements. The linear extended state observer (LESO) has the function of filtering the output signal of the system. The traditional LESO channel is added with filtering to improve the noise suppression ability, and the observer is upgraded to improve the observation ability, thereby improving the contradiction between the system response speed and controller noise suppression. In the frequency domain, the improved linear active disturbance rejection controller is analyzed through the Bode diagram in terms of stability, tracking and anti-disturbance. The theoretical analysis shows that the improved active disturbance rejection controller can reduce the effects of the noise at the controller input and system feedback. The simulation results have verified the effectiveness of the controller in noise suppression.