This study is about earthquake-proof reinforcement through structural function evaluation of an existing structure. The purpose of this study is to comparatively analyze structure reinforcement measures in consideration of safety and usability through structural function evaluation of existing structures, to offer rational measures for earthquake-proof function and to provide help in maintaining safe structures against earthquake. For this purpose, was selected for this study as an existing school building, earthquake-proof function evaluation was conducted, and measures to reinforce earthquake-proof function was offered. As for the research method, the first and the second earthquake-proof function evaluations were conducted which is an existing reinforced concrete school building. Through the abovementioned methods, earthquake-proof function evaluations were conducted, the results were analyzed and the measure to reinforce earthquake-proof function were offered(reinforcement brace, RC shear wall reinforcement). The offered measure to reinforce earthquake-proof function was applied to the subject structure, and comprehensive results were derived from earthquake-proof function evaluation regarding before and after earthquake-proof function reinforcement.