By analyzing the COD, SS, NH3N and TP in the rainwater after two processes of rainfall in a certain residential district in Qingdao, we found that the pollution degree of these 4 pollutant indicators in the initial 2mm deep rainwater is the biggest during the whole raining process and such rainwater should not be utilized. We can recycle and utilize the rainwater by decontamination triage method in the residential district after the initial rainfall period. By comparing the amount of all kinds of water consumption in the residential district and the amount of collectable rainwater, we conclude that the recycled rainwater can meet the water demand of residential district in the upstream. Once the project of urban rainwater utilization is carried on, no less than 2 million tons of tapwater will be saved annually and more economic benefits and positive social effects will be brought.