This paper studies the effects of various semi rigid column beam connections on the seismic response of space steel structure. Choosing the first order natural period, ratio of axial force and drift angle as the evaluation index, this paper uses ANSYS to analyze the effects of lateral and axial torsional stiffness on the seismic performance of steel structure under real earthquake wave. The simulation results show that the lateral torsional stiffness has great influence on the structural seismic behaviors. Thus, it can provide some certain reference for the design of ultra limit buildings.