Almost all modern water resources systems are featured as multi-objects, multi-sources and multi-users ,which should be kept in mind during decision-making process of their development and management. A decision-making model using expert systems technology for Water Resources systems management was developed in this paper. The phototype of the Water resources system used in this work is composed of a surface reservoir water supply system, a public water supply system ,three different irrigation areas and a swamp ecological area. It originally came from the idea of irrigation games and role play proposed by some British researchers in the early 70's and improved by other foreigners later on , Then it was used as the prototype of a simple but realistic and integreted water resources system management and a role play Lotus simulation model was developed based on it. The players in the role play model are Water Authority Manager(WAM), Public Water Supply Manager (PWSM) and three different groups of Farmers. Another player, System Manager, was introduced to the system in this work to make it perfect and consistent with cases in our country. This player is responsible for the overall operation,settling down conflicts among different players, controlling the system environmental quality,and making overall socialeconomic as well as environmental benefits maximal. The main objectives of the role play simulation model are focused on training different players in the game,or different persons involved in different roles within the system to become farmiliar with and to gain inside into all possible aspects concerning operation and maintenance of a typical water resources system. A decision-making model using the PC-based VP-Expert Shell was developed to extend the functions and to improve the performance of all the players on their decision-making process. undoubtedly,it is a very useful approach for modern water resources system management.