In the field of helicopter control,an attitude composite controller based on nonlinear active disturbance rejection and non-singular terminal sliding mode method is designed to solve the problem that the helicopter is susceptible to system uncertainty and most controllers are highly model-dependent.Firstly,the full nonlinear dynamics equation of helicopter is established to obtain each of the attitude channel models with disturbance term.Secondly,the framework of Active Disturbance Rejection Control (ADRC) is adopted to design the nonlinear extended state observer and the global fast non-singular terminal Sliding Mode Controller (SMC),which can reduce the dependence on the model and realize the rapid response of the helicopter attitude with excellent disturbance rejection characteristics.The simulation results show that the proposed composite controller is effective in helicopter attitude tracking and disturbance rejection.