The imbalance between water resources and water demands in the river basins cause conflicts over water allocation to various users. Game theory is considered as a new tool for conflict resolution in the context of water resources. In this study different game theory methods are used including the cooperative and non-cooperative approaches to water allocation in a river basin. To develop a cooperative approach even four scenarios are used which consider irrigation improvement, withdrawl limitation from aquifers and development projests to transfer water into the basin.The Bankruptcy method is a cooperative approach based on fairness allocation while estate is fewer than stakeholder’s claims. Proportional(Pr), Approval Proportional(AP) and Constrained Equal Award(CEA) method are the types of Bankruptcy approach. Two first methods provide equal ratio of stakeholder’s demands and in another one, the stakeholders with low claim value will gain more benefit than others. Results show that the stakeholders approximately gain 50% of their claims in drought period and 80% in normal situation with Pr and AP methods. In CEA method, stakeholders like Industrial and domestic sectors out of the basin with low claims completely reach their demands. Then these methods are evaluated by Stability index(SI) and it shows that AP is proper method for drought periods and CEA for normal periods. In order to to examine fifferent water allocation policies, Separable Cost -Remaining Benefit(SCRB) based on core method is used. This method is based on stakeholder’s cooperation and economic performance. Cooperation condition in this approach is not claiming on complete water demand. So the stakeholders with high claims and high economic efficiency are effective on forming coalitions. The result of this approach is compared with initial allocation based on water rights and historical laws. This game theory approach increases benefits of using water for system and have better performance than initial allocation in economic view. All of the cooperative approaches are evaluated with social choices methods and the results show that CEA is a proper allocation method. Graph Model Conflict Resolution is implemented as a non-cooperative game theory in a basin with two stakeholders including Isfahan Regional Water Authority and Isfahan Agriculture Organization.with conflict analysis of this game, equilbrium cenario will be presented.In this scenario tell Agricultural sectors can develop the cultivated area with improvement in the irrigation efficiency while Isfahan Regional Water Authority should control- limit water withdrawal from the aquifers. Key Words : Conflict Resolution, Game Theory, Water Allocation, Cooperative, Non-Cooperative.