For more than two thousand years, it has been playing the role of flood control and irrigation, making Chengdu Plain a "land of abundance" with thousands of miles of floods and droughts. Up to now, the irrigation area has reached more than 30 counties and cities, covering an area of nearly 10 million mu. It is the oldest water conservancy project in the world, the only one preserved and still in use. Its characteristic is that there is no dam to divert water, which embodies the diligence, courage and wisdom of the working people of Han nationality in ancient China.