UAV longitudinal pitching Angle control is the foundation of the flight path control. In this paper, we proposed an UAV longitudinal pitching Angle control system based on nonlinear ADRC to solve the UAV trajectory tracking control to rely too much on mathematical model and the accuracy of measurement. First, we set up UAV flight dynamic mathematical model; then according to the order of dynamics equations choose corresponding ADRC. The pitching angle control loop was set up. Finally, the simulations results compared with the traditional PID control system, with four different distract signals of winds. The results of experimental show that the ADRC system has better control effect and robustness.