The four-element connection coefficient was introduced into the evaluation system of water resources sustaining utilization. Combined with the improved fuzzy analytic hierarchy process ( FAHP ),the paper calculated the weight of every evaluation index, constructed the weight average link degree, and then determined the class of sustainable utilization level of water resources by weight value, finally established the evaluation model of fuzzy four-element link coefficient for the sustaining utilization of water resources. Taking Yan''an for example, the paper evaluated the state of water resources utilization of Yan''an in 2005and 2010. The results show that the sustainable utilization level of water resources is turn from weak to moderate, and sustainable situation has been improved. The results are basically consistent with the fuzzy comprehensive evaluation method and artificial neural network method. The fuzzy four-element connection number method is easy to calculate and can overcome the arbitrary of establishing weight, has high utilization rate of information and is effective and feasible to the evaluation of sustaining utilization of water resources.