Recently, demand of expanded balcony in apartment has been increased to urban residents and various legal recourse is set up to improve safety of glass in building. Taking this circumstances into consideration, this study is to suggest a practical window system with laminated glass for balcony in building. Conclusions of this study are as follows. 1) Considering characteristics of safe glass railing, laminated glass(CC44.2) including plate glass over 4 mm and middle pane over 0.78 mm was available. 2) An efficient system to building exterior window was a double-glazed envelope system, in which CC44.2 laminated glass was installed indoor, and plate glass was installed outdoor with 5 mm or 6 mm allowing for wind pressure resistance of high-rise building, was available. Especially, considering weight of window and pattern of body collision, this system to use middle frame formed only bottom part(120 mm from ground) was practical alternative. It was recommend that soundproof, safety and space utilization of proposed system were more efficient that those of current double-window system.