Abstract: For studying the aseismic performance of the prefabricated steel frame with inclined support joints，the Pushover analysis was applied on one 30-story prefabricated steel frame and compared with analysis results of the frame without inclined support． Analysis result showed that under 7-degree rare earthquake，the maximum drift was 1 /223，which was less than 1 /50 specified by the code，hence this building structure could meet the principle ofno collapse under seldom earthquake actionin the national seismic design code; the arrangement of inclined support could reduce the deformation of the structure under severe earthquake，and the top displacement and the maximum drift of the structure were reduced by 33. 4% ～ 38. 1% and 19. 3% ～ 40. 1% respectively． Most of plastic hinges occurred on positions of web members of the truss girder，and frame columns were in elastic stage．