This study aims to find out actual conditions of environmental-friendly design on outdoor space of housing estate, and then to propose the direction of environmental-friendly design in order to construct the adequate environmental-friendly housing estates. First of all, this study investigated the environmental-friendly design elements on outdoor space of housing estates through literature survey and selected 9 major elements based on the result of the investigation. And then 15 KNHC housing estates were analyzed to find out design actualities of environmental-friendly elements. Major results of this study are as follows. 1) The environmental-friendly design elements were highly adopted in outdoor space of housing estates. The adoption rate of environmental-friendly design elements is 81.0% in average. But, 5 major elements were passively adopted out of 9. 2) According to the comparative analysis of KNHC housing estates, The adoption rate of environmental-friendly design elements was similar in metropolitan housing estates and non-metropolitan housing estates. But, the adoption level of environmental-friendly design element in metropolitan housing estates was higher than one in non-metropolitan. It shows that metropolitan housing estates are more activly adopted in 6 major elements. 3) According to the comparative analysis of design method of KNHC housing estates, The adoption rate and the adoption level of environmental-friendly design elements by turn-key design method and competition design method were higher than by general design. It shows that the housing estates designed by turn-key and competition design method are more activly adopted in 7 major elements.