Abstract: In order to overcome the influence of gravity factor on robot arms and improve tracking performance of robot arms, an accurate online gravity compensation other than fixed value gravity compensation PD control strategy is presented. In this method, robot space geometry and torque balance principle are used to deduce the gravity compensation function of each joint. Then the control design is applied to the right arm model of the deicing robot. The experiment results show that the deicing robot's right arm with accurate online gravity compensation control design has better control performance than the past researches and that has no online gravity compensation, and has better tracking performance of continuous signals.