The rainwater in Liaoning Technical University Yulong school teachers’ apartment was selected as the research object. By calculating the rainwater volume in the position of the roofing, the road and the grassland and the monitoring result of water quality in different area, we get the water runoff characteristics and water quality characteristics in the whole teachers’ apartment. Associated the comprehensive utilization way of rainwater in this apartment, we work out the rainwater harvesting scope and method and conduct a coagulation test based on the above. Select PAC as coagulant and the dosage is 40mg/L. Stir with medium speed 150r/min and last 3min or low speed 50r/min 15min, then let stand for 15min. The result show that under above condition the removal rate of rainwater turbidity is 91.3%, the removal rate of COD is 61.2% and the removal rate of NH3-N is 29.3%. The reference treatment process is given according to the above result and the water quality meets the water quality standard of the city. The results could provide valuable reference for comprehensive utilization of rainwater in the north water shortage city.