Abstract: In this paper, the shaping methods of dual-offset Gregorian antenna are studied, and an effective shaping method is presented. Based on the total differential condition, the mapping relationship between the main reflector and the sub-reflector is derived, and according to energy conservation, Snell's law, and the equal optical path condition, profiles of the main and sub-reflector can be obtained. Design examples are given, and the simulation results show that the proposed method effectively control the amplitude of aperture field distribution, and realize the expected antenna pattern.