In order to achieve precise trajectory tracking control for a quadrotor in the presence of external disturbances affecting and system model parameter uncertainty, a nonlinear trajectory tracking controller for the quadrotor is designed and verified. In this paper, the mathematical model of the quadrotor considering the actuator characteristics is firstly established and the virtual control is mapped to the motor control. Then, a nonlinear trajectory tracking controller based on integral backstepping method is designed by adding the integral term to the controller, to eliminate the errors caused by the uncertainty of model parameters and external disturbance. The numerical simulation results prove the feasibility of the method. Finally, the designed nonlinear trajectory tracking controller is applied to the QBall2 quadrotor flight test. The flight test results illustrate the effectiveness of the method, in which the tracking control accuracy is improved under the external disturbances and system model parameter uncertainty in the practical environment.