Many steel structures have been faced the problem of deterioration in Japan. Severe damages will be caused in such deteriorated structures subjected to huge earthquake. It is necessary to secure safety of such structures against earthquakes. However, 2 dimensional horizontal behavior of seismic response of structures with damages by corrosion has been hardly researched. In this previous study, experiments intended for rectangular steel bridge piers, with damages by corrosion in the corners were conducted in order to evaluate 2-dimensional behavior. Therefore, the seismic response analysis by dynamic analysis was carried out in order to clarify the seismic response behavior of the steel pier damaged by corrosion using numerical analysis. As a conclusion, it is found that the seismic performance of steel bridge piers corroded greatly deteriorates. Especially, the analysis results in inputting two directional waves were different from the results in inputting one directional wave. So it is important to accurately understand the seismic performance of corrosion-damaged steel piers.