The hydrological cycle system in the city is generally characterized by quick runoff, bad infiltration, low evaporation rate, and so on. It is caused by sealing greens up with pavements. Also, there are lots of contradictory environmental problems, such as inundation, the lack of underground water and dryness in the city, caused by the urban drainage system which is mostly focused on the quick draining off rainfall. In addition, the technique joining rain and sewage, which has more dangers of inundation, occupies 66% between two Korean drainage systems which consist of joining and dividing system. There has been some need to convert the present drainage system into the environmentally friendly hydrological cycle system. This is a theoretical study to examine some foreign cases and suggested applicable methods in our country, focusing on the environmentalyl friendly system of rainfall drainage. The precipitation treatment system can be made up of some possible phases choosing from premanagement, utilization, infiltration, retention, and inducement phases. Therefore, this study mostly focused on infiltration, retention, and inducement phases. It is necessary to suggest the multifunctional utilization of outdoor spaces, especially applying in new constructing and re-constructing residential estates.