The multi-hierarchy and multi-objective fuzzy theory was applied to establish a multi-hierarchy and multi-objective fuzzy evaluation model of regulated deficit irrigation comprehensive benefits. Using the information entropy theory, the impersonality weights of all hierarchy evaluation indexes were obtained, and the subjective weights given by experts to attain the comprehensive weights for the method of multi- hierarchy evaluation indexes were combined, the reliability of the model evaluation results was improved．At the same time, the model was used to evaluate and order the comprehensive benefits of regulate deficit irrigation integration benefits of mini-watermelon with different water deficit treatments in autumn of 2007. The results indicate that the water deficit can improve fruit quality, but the serious water deficit and moderate water deficit would decrease yield in fruit spreading growth stage. The water deficit has little influence on yield and quality of fruit in fruit maturing stage. During the seeding stage, blossoming and bearing fruits stage, fruit spreading growth stage and fruit maturing stage, the irrigation standard of 0.75 Ep , 0.75 Ep , 1.25 Ep and 1.00 Ep was adopted respectively, and could get the perfect comprehensive benefits of regulate deficit irrigation integration benefits.