Water resources management in China still maintains the characteristics of planned economy. The state allocates, manages and accounts water resources. This makes the water-saving enthusiasm of water users weak and water accounting inaccurate. The construction of a water-saving society has entered a bottleneck period. From the perspective of national governance, this paper proposes to build a modern water resources governance system with the water right system as the core, and endow water users with the ability to carry forward the surplus water use indicators within the control indicators to continue to use next year or transfer them in the water right market, so as to establish the incentive and restraint mechanism of water rights. Further, this paper proposes to calculate the distribution and use of water resources of water supply and consumption units based on the accrual basis, and constructs General Purpose Water Accounting system with micro water related units as the accounting subject, including water resources accounting, audit and external information disclosure, so as to better reflect and supervise the distribution and use of water resources and make the control indicators of water resources rigid and flexible. The modern water resources management system of division and cooperation among government, market and society is constructed. Taking Hetao irrigation area as an example, General Purpose Water Accounting reports are compiled to show the ideas and methods of modern water resources management. Modern water resources management system provides a fundamental solution for the construction of water-saving society.