In order to improve water quality of Lake Dianchi,the characteristics of non-point source pollution from flower green-house area along the east bank of the Lake Dianchi were explored.The Storm Water Management Model (SWMM) was built with measured rainfall runoff data to simulate the quantity and quality of rainfall runoff under both continuous and typical rainfall condi-tions in a flower greenhouse area in Dounan Village,Chenggong County.The results indicate that:1) The Nash-Sutcliffe efficiency coefficients of the flow,chemical oxygen demand (COD_Cr),suspended solids (SS),total nitrogen (TN) and total phosphorus (TP) in the SWMM are 0.858,0.835,0.803,0.712 and 0.752,respectively,so that the SWMM model can be used to predict the quantity and quality of rainfall runoff in the area.2) The average runoff coefficient of the area is 0.59.The annual loads per unit area of COD_Cr,SS,TN and TP are 118.34,82.90,54.64 and 5.46 kg/(ha·a),respectively.TN and TP are major pollutants.3) The peaks of every pollutant concentrations appeared earlier than the flow peak so controlling the pollutant load should be ad-vanced,especially for TN and TP controlling.