In this study, verification was performed regarding overheating phenomenon which can be caused in double skin facade in summer through management survey targeting on multistory double-skin facade. Also, the researchers made Energyplus simulation model with same airflow network with targeting double facade and verified its validity through comparison. Finally, natural ventilation performance and air conditioning energy performance by top blowdown opening plan was analyzed by applying evaluation alternative to the simulation model. As a result of analysis, as upper part blowdown model flexibly reacts toward influence of air and exterior wind pressure, total pressure distribution increased gradually and performance of natural ventilation was improved. It indicates good performance in the aspect of natural ventilation rate (49.3% of improvement compared to Baseline) and cooling load (5.9% improvement compared to Baseline).