Dujiangyan, located in the west of Dujiangyan City, Chengdu City, Sichuan Province, is located on the Minjiang River in the west of Chengdu Plain. It is a huge engineering system composed of canal head hub (fish mouth, sand flying weir, bottle mouth), irrigation area diversion channels at all levels, all kinds of engineering buildings, large, medium and small reservoirs and tangerirs, etc. The canal head covers an area of more than 200 mu. It is responsible for irrigation of more than 11.3 million mu of farmland in 40 counties (cities and districts) in 7 cities (localities) in the central and western parts of Sichuan Basin, water supply for many key enterprises and urban life in Chengdu, flood control, power generation, water bleaching, aquatic products, aquaculture, forest fruit, tourism, environmental protection and other target comprehensive services. It is an irreplaceable water conservancy infrastructure for the development of Sichuan's national economy.

During the reign of Queen Zhao of Qin (276-251 BC), Li Bing, governor of Shu Prefecture, summarized the experience of his predecessors in flood control and organized people on both sides of the Minjiang River to build Dujiangyan. In the Tang Dynasty, the flying sand weir was built. After the founding of the People's Republic of China, and the construction of industrial drainage canal, Wai Jiang gate, flying sand weir industrial diversion temporary sluice. In order to effectively manage and maintain the operation of Dujiang Weir, weir officials and annual repair systems have been set up.

Dujiangyan is the world's oldest, the only remaining, dam - free water diversion as the characteristics of the grand hydraulic project. It makes full use of the local geographical conditions of high in the northwest and low in the southeast. According to the special topography, water veins and water potential at the mouth of the river, it takes advantage of the potential and leads the water. There is no dam for water diversion and artesian irrigation, so that the dike, water distribution, flood discharge, sand discharge and flow control depend on each other, which is a system to ensure the full play of the comprehensive benefits of flood control, irrigation, water transportation and social water use. Its greatest point is that the weir has been built for more than 2250 years, and it is playing more and more benefits.

Dujiangyan is a World cultural Heritage, an important part of the World Natural Heritage, a world irrigation project heritage, a national key cultural relic protection unit, a national scenic spot, and a national AAAAA level tourist attraction.