The invention provides a precise measurement reference design method for an SAR satellite, and the method comprises the following steps: 1, respectively setting reference blocks in regions of the external surfaces of four end parts of an antenna frame, setting a prism installation boss on the frame, controlling the levelness of the reference blocks and the levelness of the boss and the reference blocks in a mode of combined machining; 2, leveling the antenna frame, enabling a main reference prism of the satellite to be installed on the boss of the antenna frame through the reference blocks at four end parts of the antenna frame and the tool conversion, and controlling the levelness of the main reference prism and the reference blocks. The method can achieve the high consistency of the coordinate system of the main reference prism with the coordinate system of a load antenna, directly eliminates the installation deviation between the main reference prism and the load antenna. A single-chip computer with other precision on the satellite and the precision of the load antenna, relative to the on-orbit to-be-reached target precision of the whole satellite, achieve the unification, thereby reducing the transmission links of precision errors, and improving the precision measurement efficiency of the whole satellite.