Abstract: Low impact design or development(LID) of rainwater resources helps to protect the natural water and reducing water scene design, and forms self-regulation of waterscape sponge. Nature imitating waterscape balance analysis equation was built based on the principle of water balance, exploring the catchment area of rainwater collect flow optimal value, thus providing a reference for waterscape design of water. By the water balance core thought the law of conservation of mass, that the regional total input of water is equal to the total output of water, water balance analysis method of quasi natural water scene was introduced in this paper, a practical example that the main entrance landscape area of Xi Shui Qing Mount Forest Park was given to discuss water balance analysis in the application of parametric design of the water.