Aiming at the attitude control problem of quadrotor unmanned aerial vehicles under the conditions of model uncertainty and unknown external disturbances, an improved linear active disturbance rejection attitude control method capable of realizing error-free disturbance tracking has been designed. Firstly, the error correction mechanism is introduced into the extended state observer to achieve disturbance-free tracking and estimation of the system, and the Levant differentiator is used to accurately extract the input signals of the controller. The cascade control strategy is adopted to decompose the attitude control into a cascade dual-loop control structure, that is, the angular velocity control is the inner loop and the angle control is the outer loop, thereby improving the anti-interference ability and robustness of the controller. Based on the semi-physical simulation environment, the attitude control effects under different disturbance conditions are simulated and tested. The simulation results prove that the controller designed in this paper has high control accuracy and stability and can meet the requirements of the attitude control of quadrotor unmanned aerial vehicles.