Abstract: The mechanical load deforms the structure of the large aperture reflector antenna, and then affects the electrical performance of the antenna. To address this issue, a partitioned active subreflector compensation scheme and its associated shape design method are proposed. It overcomes the limitations of the traditional subreflector position adjustment scheme, which can only correct large-scale shape errors of the main reflector. Firstly, the large-scale low order distortion of the main reflector is corrected by rigidly adjusting the position of the initial subreflector. Subsequently, the adjusted subreflector is divided into several panels, and the pose of each panel is adjusted by calculating the position parameters of each panel, so as to eliminate the residual surface error of the main reflector, and the shape of the subreflector is ultimately determined by the calculated panel positions and the adjusted panel poses. Numerical results demonstrate that this method can successfully achieve the shape design of the subreflector, and the new scheme can effectively correct the main reflector error, thus enhancing the electrical performance of the antenna.