Geosynchronous synthetic aperture radar (GEO SAR) satellites have the characteristics of large width, high gravity and continuous observation. In order to meet the imaging requirements of GEO SAR satellite, three imaging attitude control modes, including yaw-roll guidance, pitch-roll guidance and ground target point pointing are designed for the attitude and orbit control system. In the ground test stage, the indexes of the three attitude control modes cannot be evaluated by the traditional three-axis attitude angle. Based on the imaging geometry of GEO SAR satellite, an index evaluation method for attitude control of GEO SAR satellite is presented in this paper. This method can quickly evaluate the above three SAR imaging attitude control indexes.