As global warming rises, many nations are turning to green technologies which can reduce greenhouse gas. In step with such development, construction industry of Korea is planning to reduce CO2 emission. Multi-residential housings account for more than 50% of all housings in Korea and most of such housings have adopted bearing wall system design. However, bearing wall apartments have disadvantages, such as inflexible architectural plan, maintenance and remodeling difficulties. Such disadvantages actually call for a new structural system alternative. This paper proposes a new composite frame system for multi-residential housing of tower type. The purpose of this research is to suggest a new composite frame system capable of reducing of CO2 emission and analyze the amount of resultant CO2 emission reduction through its application. As a result, CO2 emission of the composite frame apartments of tower type is found to decrease by approximately 20% in comparison with bearing wall apartments. In the area of multi-residential housing, the new composite frame system will make significant contribution to the reduction of CO2 emission. In addition, new composite frame apartments of tower type will provide a framework for 'Sustainable Development' with consistency by improving flexibility of architectural floor plan, reducing CO2 emission and construction wastes.