This paper investigates the attitude control problem of a quad‐rotor unmanned helicopter. In response to adverse factors, including the lumped disturbance, inertia parameter uncertainties, and the partial loss of rotation effectiveness, an adaptive compensation control strategy combining the terminal sliding mode technique and the input shaping method is proposed. Specifically, a group of updating laws using an adaptive mechanism is added to adjust the control strategy in a manner conductive to attitude stability and performance preservation in the presence of adverse factors. The key features of the proposed control strategy are that it is independent from the knowledge of actuator faults, and adaptive compensation control is achieved without the need for online identification of rotor failure. The finite time convergence and stability of the attitude tracking errors are proved by using Lyaponov's method. Finally, the simulation results demonstrate the effectiveness of the proposed control strategy.