Yuan dynasty. As early as the Yuan Dynasty, there was a picture of Tian Yunxu in Wang Zhen's Agricultural Books. At first, the building in Yuntianwei was relatively simple, just building dikes to block water. In the Five Dynasties, the building technology of Yuntianwei has made great progress. Yuntianwei, which is integrated with dikes, culverts and ditches, is large-scale and well-built. Yun Tian Li Fei played a very important role in the history of human farming.