Abstract: Based on some comparisons between the advantages and disadvantages of the two structural systems and the shaking table tests had verified that the preliminary design has a good seismic performance,the special concentrically braced steel frame with pinned connections was selected for the main building of a large thermal power plant.Taking the detailed design of this structure as prototype,the numerical analysis had been conducted.The results show that,this structure is the one with torsion and vertical mass irregularity,but considering that no members yield or out-of-plane buckling under frequent earthquakes,the inter-storey drift angles are all less than the limit values of the GB 500112001 under frequent and rare earthquakes,the detailed design is reasonable and it is predicted that the structure can meet the requirements of no damage under frequent earthquake and no-collapse under rare earthquake.The results of the present study once again show that if the design is reasonable,the special concentrically braced steel frame with pinned connections has a good seismic performance in the seismic region with aseismic fortification of intensity 8 and the building height of such a structure can exceed the required limitation height of a 12-story civil building.At last,some suggestions on the seismic design method of connections are proposed.