Abstract:Though most people are concerned with its environmental, biological, anti-seepage and landscape effects, the lake's plastic sealing project in Yuanmingyuan Ruin Park connected with the ruin's function, wetland's eco-service, water saving and exploring strategies, and the park's management instruments. It was caused by the human-centered philosophy, fragmented institution, reductionism dominated technology. To solve the problem, a kind of watershed based and complex ecosystem oriented integrative planning, construction and management must be carried out. A constructive wetland treatment of the output water from a nearby sewage treatment plant was suggested to add clean and flowing water to the lakes. The action will result in vitalizing the city's water system and providing better eco-service while maintaining the sustainability of the park.