Based on integral sliding mode method and Extended State Observer (ESO)an active fault-tolerant control system is developed to implement position and attitude control of quadrotor UAV with actuator failure.A nonlinear model of UAV with actuator failure is establishedand a Sliding Mode Control (SMC) method with strong disturbance rejection ability is used to design basic controllers for the inner loop of attitude and the outer loop of position.In order to reduce the errors of the steady-state systeman integral sliding mode controller is constructed.The boundary layer method is used to suppress the chattering of SMC algorithmwhile ESO is used to estimate the total internal and external disturbances and the interference of actuator failure in real time and then compensate for the controlled variables.It is verified by Lyapunov stability theory that the flight control system can converge rapidly to a stable stateand the effectiveness and robustness of the developed flight control system are verified by some numerical simulations.