Abstract: To solve the problem of inertia coupling between the pitch control loop and roll control loop for small duct-fan UAV, the simple adaptive control (SAC) method was adopted to design the model reference adaptive controller for the control loop of the attitude angular velocity of the UAV. This control loop could be able to follow the output of reference model stably under the influence of the uncertain disturbance and parameter perturbations. Meanwhile, feed-forward decoupling in series to the constructed the reference model, the UAV could follow the reference model to be decoupled synchronously, and thus the effective control to the attitude angular velocity and the attitude angle of the UAV could be achieved. The simulation results show that the control law can make UAV attitude stably follow the reference model output, and it is not sensitive to parameter perturbation. The control system is strongly adaptive and robust.