When the flaps are lowered during takeoff or landing phase, ailerons on the both sides can be deflected simultaneously downward into the airstream to increase wing camber, supplementing flaps with lift augmentation. Takeoff or landing speeds and field length are reduced, thus performance is improved by using aileron droop. The research document introduces development process, basic principle and functional implementation on aileron droop function of X and Y civil aircraft in order to analyse aileron droop function specifically.