Abstract: The design of lake eutrophication prevention system is the key for the construction of man-made lake, which is also the fundamental guarantee to achieving the goal of water quality for man-made lake. Jinsha Lake, an artificial lake located in Xiasha District of Hangzhou City, was taken as a research object, and a water pollution prevention system integrated with lake pollution control, ecological water diversion, morphology design and ecosystem construction was proposed according to  the low quality of the lake water. The design ideas, determination methods and main conclusions of the system's each part are explained. The achievement of the water quality goal for the artificial lake is assessed based on the water quality data measured after the lake construction. The design idea and analytical approach could be referred to by other similar cases.