Rainwater harvesting the benefits of using the project can be divided into economic, social and ecological benefits of three parts. In the analysis and comparison of economic, social and ecological benefits as well as on the basis of inputs, arguably rainwater harvesting project the necessity and rationality. Domestic water supply of the economic benefits of rainwater harvesting project before the project mainly includes fetching water saving labor and expense (animal, car HE tractor cloud water fuel), as well as improving water quality by reducing medical costs. Production purposes, water supply rainwater harvesting projects mainly in drought resistance and yield economic benefits (including the adjustment of agricultural structure after appreciation), livestock farming. Small-scale processing industry development. Benefit calculation of benefits should be reasonably assessed. Drought should increase efficiency by multi-year average, the design and the severe drought years of the annual output value by calculating a weighted average. Social benefits mainly reflected in rainwater harvesting project is completed promote poverty alleviation and development, rural economic development and rural spiritual civilization. With water, can promote the local agricultural structure adjustment and farmers to get rich. Develop water-saving high-efficiency agriculture, improve agricultural production conditions of farmers living environment, and promote a new socialist countryside construction. Eco-efficiency is the Project on the local ecological environment, such as to alleviate water conflicts, reduce soil erosion, improve sanitation conditions, and other benefits.