In this study, the seismic performance of RC school buildings which were not designed according to earthquake-resistance design code were evaluated by using response spectrum and push-over analyses. From the results of analysis, the efficiency of the seismic retrofitting methods RC shear wall, steel frame, RC frame and PC wing wall for existing RC school buildings was evaluated and analysised. The analysis result indicate that the inter-story drift concentrated in the first floor and most plastic hinge forms in the column of the first story. And results of analysis of the efficiency of the seismic retrofitting indicate that inter-story drift significantly reduced and ductile behavior is expected.