The quadrotor UAV has complex aerodynamic characteristics and is prone to be interfered, which will greatly affect the stability of the UAV.In order to enhance the anti-interference ability of the UAV's attitude control system, an attitude control system is designed based on the improved Active Disturbance Rejection Control (ADRC).The proposed method combines the traditional ADRC technology with the global fast terminal sliding mode control technology, which is used to optimize the feedback control law of the nonlinear state error in the ADRC system.In addition, the ADRC system is redesigned, and its stability is proved by using Lyapunov theory.Experimental results show that the improved ADRC system has faster response speed and stronger anti-interference ability in attitude control.