Abstract: For critical buildings, due to the special shape demands, the structural layouts often become irregular. On the other hand, because of the importance of their function, the seismic design criterion of these buildings is higher than normal ones. The designer of structure usually encounters difficulty and challenge in the seismic design. Two approaches to improve the seismic performance of buildings were presented: One is to reallocate the bending stiffness of the local structural members in order to make the distribution of structural stiffness uniform inherently though the appearance is irregular. The other is to add some oil dampers to buildings, which may provide additional damping for structures. The analysis results indicated that the structural seismic performance could be obviously enhanced due to adoption of above approaches, and the sections of structural members ( column, beam) could be reduced, and then to get better cost performance.