Abstract: The structure of metal space frame (MSF) has a significance influence on the electromagnetic properties of radomes when the overall size is determined. In this paper, the effects of different frame structures on scattering characteris tics are studied based on the topological structure. On the basement of regular and irregular MSFs with the same mechanical parameters, the method of induced current ratio is employed to calculate the induced current distribution on the different posi tions of frame, and the scattered field of frame is obtained. The result proves that the scattering energy in far-field is dispers ed to the side-lobe area far from the radiation direction because of the quasi-random arrangement of struts in irregular MSF. This dispersion leads to a smaller influence on the radiation field near the radiation direction. The performance of radomes can be improved with the employment of metal frame which is designed by the irregular division method.