By collecting the literatures of reform of irrigation and water conservancy in China, the current dilemma of reform of irrigation and water conservancy is summarized, namely the tension caused by the top-down mandatory system and the bottom-up induced system. The formation of this tension is resulted from the interaction of the institution, organization and society: the institutional path dependence leads to the weakness of rural organizations, change of the socioeconomic environment increases the transaction cost of reform, and the collapse of organizations leads to the failure of the new system. Finally three suggestions for solving the dilemma of the reform of irrigation and water conservancy are put forward, that is, breaking the path dependence of institutions, strengthening the organization contact and attaching great importance to the social environment.