Abstract: The water resources and socio-economic system (PRD) in river valley is studied in this paper by system dynamics (SD), and based on it the dynamic behaviors of PRD system in river valley are simulated under different conditions, which can be the basis of solving the problem of river valley PRD system. Taking Guanzhong segment of the Weihe River valley as an example, three PRD system models (the lineal-growth model, the feedback-growth model and the water diversion coupling model) are respectively set up by SD, and simulated by the Venple software. The lineal-growth model based on government planning objective is the pattern that society-economy can develop at a super-speed, but it can also continuously enlarge the gap between the demand and supply of water resources. The feedback-growth model could adjust to the target of socio-economic development according to the conditions of water resources carrying capacity within the river valley, yet it is difficult to fulfill the developing and driving mission that Guanzhong area takes on. The water diversion coupling model introduces water resources outside, by which the situation of water shortage can be improved clearly, also the socio-economic development can keep on increasing at a sustainable higher speed, so it is an effective way to solve the PRD problem in Guanzhong area, however, the synergy of water diversion project and society-economy becomes the critical problem to be solved at present.