The purpose of this study is to evaluate the sound insulation performance and present fundamental data for sound insulation plan about open and close windows of inner facade and outer facade of Double-skin Facade system applied to multi-story type. The Headquarter of Green Building and the Energy Saving Building in the Korea Institute of Energy Research was selected for experiment. Measurement method which are specified in the Korea Standard 2235 were selected for this study. As the result of this study, 1) Sound insulation performance of Multi-layer type of Double-skin Facades is very excellent about outdoor noise. 2) Vertical level is higher, it shows that more decreases sound pressure level.