Abstract: With the application of concrete-filled steel tubular member to mega-frame structures,the connection forms of main beam-column can be classified as welded rigid connection,bolted gemel connection and semi-rigid connection.The results of a 24-story mega-frame structure with 4 spans were calculated by the universal finite element method of MIDAS,the different structural character values such as structural free vibration periods,structural displacements and structural moments were compared,the influence of connection form of main frame beam-column on behaviors of mega-frame structure were discussed,and smoe reasonable suggestions were put forward to guide engineering practice.