Currently the seismic performance evaluation for existing buildings are being made simply through the review of the analytical technique corresponding to design specifications on beam, column, shear wall, joint and so on. Also the seismic performance is evaluated to 4 steps as immediate occupancy level(IO), life safety level(LS), collapse prevention level(CP), collapse occurrence level(CO). However, in case of a structure being used for a number of years after construction, which may have partial damages and durability degradations may show significant differences between the analysis results and the actual behavior during an earthquake. Therefore, a improved seismic performance assessment is proposed based on risk assessment and seismic performance techniques since more systematic evaluation and condition assessment are required, and thus the practical and economical seismic retrofit measures for the existing facilities and for the reasonable seismic design as well are to be developed more than ever before.