| This paper first presents the uncertainty of water resources and the process of fuzzy set theory in this field, then analyzes the current conditions of agricultural water resources and its sustainable developments in our country. Based on the researches in this field, considering its character of multi-objective, multi-layer, multi-function and multistage, this paper mainly deals with the fuzziness and stochastic uncertainty of agricultural water resources system. The major contents and research results are as follows:1 Based on Chen Shouyu's fuzzy set theory, this paper presents a fuzzy optimal multi-dimension and multi-objective dynamic programming model, then two methods are given. One is multi-dimension maximum sum of relative membership degree; the other is staged multi-dimensional fuzzy optimization method. The first method is suitable for the static program that time is not involved, and the second method can be used to solve any multistage problem, especially for those problems time is involved, In the end, these methods are explained in detail one by one. These methods enlarge the range of fuzzy optimal theory.2 Inadequate irrigation schedule is not only the key for deficit irrigation, but also the basis for optimal allocation of agricultural water resources. Because of the unreasonable restriction of actual models, soil water content at the end of the stage that its sensitivity parameter is small is always close to the wilting coefficient, this makes planting risk. To deal with the planting risk of inadequate irrigation schedule, this paper develops a new multi-objective model for inadequate irrigation schedule programming, and uses the staged multi-dimensional fuzzy optimization method to get the decision-making. The case study proves that the model is reliable, and the method is applicable.3 Based on analysis of the relationship between agricultural water resources and its sustainable development. This paper presents a multi-objective fuzzy optimization model for planting structure and water allocation, which overcomes the shortcoming of current models that only considered the economic object, ignored the society and environment objects The case study proves that the model is reliable, and the results are reasonable and practical. And it is useful for agricultural water management and its sustainable development.4 In order to make.the decision adjust to the practice, and use the limited water resources more rationally. A multi-objective fuzzy decision method for irrigation district is presented considering fuzzy connection, then a method is given to get the changeable objective weight of each stage. This model can solve the decision in conjunctive use of ground and surface water. The result of the case study is satisfactory.5 Considering the characteristic of large complex system, based on Chen's fuzzy pattern recognition theory, a multi-layer and multi-objective fuzzy pattern recognition method ispresented in this paper. It can resolve the optimum selection in decision-making in complex large system, which contains many objects and many .factors that are usually at different layers. During the process, a method named subject combined with objective is used to get the objective weight. Then the model is used in selecting water saving irrigation technology. The case study proved that the model is reasonable and the method is practical.6 Based on the fuzzy optimal multi-dimension and multi-objective dynamic programming model, this paper presents a stochastic multi-dimensional and multi-objective fuzzy dynamic programming, it can be used in decision making among complex systems, which characterized by random inputs. Two different methods are given, one is named stochastic maximum sum of relative membership degree, and the other is named stochastic multi-dimension staged fuzzy optimization theory. They are explained in detail and can be used under different conditions. These two methods enrich the fuzzy optimal theory.7 Because rainfall affects crops deeply and the rainfall is st...
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