Linear extended state observer (linear extended state observer, LESO) is the core component of linear active disturbance rejection control (linear active disturbance rejection control, LADRC), and its performance is critical to the control effect. The linear ADRC is applied to the speed loop of the permanent magnet synchronous motor control system with a double closed-loop control strategy. By adding a scale factor to the linear extended state observer, the utilization efficiency of the observed signal and the observation speed is improved. On this basis, a hybrid switching strategy is adopted to achieve a smooth transition between the traditional ESO and the improved ESO, avoiding the motor speed imbalance and motor chattering caused by direct switching. Finally, the improved ADRC strategy and the traditional ADRC strategy are compared and analyzed through simulation, which verifies the effectiveness and superiority of the improved strategy.