This study mainly dealt with the relation between Environment (Human and Nature) Chang and Policies, by case about the rule of irrigation, called 'distinguishing water and applying apart' (清濁分用) in Shanxi Hejin County (山西河津縣). In 1389, the rule of irrigation was set up, to solve the situation, which the upstream villages used more water for less costs, but the downstream ones reversed. When time past, Environment Chang made local government adjust the rule for reality. But that created new problem, downstream villages were working the rule of irrigat ion, manipulated their opponent, satisfied themselves, and cheated the governor. Downstream villages took advantage of upstream villages in this system, that was symbol of equity and justice.