A design method of attitude controller for quadrotor UAV based on cascaded linear Active Disturbance Rejection Controller (ADRC) is proposed, and the position controller is designed by using Proportional-Integration-Velocity (PIV)control to realize the trajectory tracking control of quadrotor UAV.For the attitude control system, a Linear Extended State Observer (LESO) is designed for pitch, roll and yaw channels to observe and compensate for the internal uncertainties and external disturbances in real time.For the position control system, the PIV control algorithm is used to design the controller and achieve stable tracking control of translation variable.The stability of the cascaded ADRC is analyzed and explained.Finally, trajectory tracking experiments on Quanser flight control experimental platform verify the effectiveness of the proposed method.