Abstract: In order to quantitatively evaluate the comprehensive benefits of domestic water saving, the connotation and the concept of domestic water saving were determined by considering the synergistic effect of water saving and wastewater reusing.The concept and evaluation method of whole life cycle were introduced, and a comprehensive evaluation system for domestic water saving benefits was proposed.The evaluation indicator system consisting of three levels of “objectives-criteria-indicators” was constructed, based on the five connotation criteria, namely, water saving and supply assurance, water saving and loss reduction, water saving and efficiency enhancement, water saving and emission reduction, and water saving benefits.The connotation and the calculation method of “water saving cost efficiency ratio” were proposed innovatively.The method of “single index quantification-multi weight calculation-multi index comprehensive-grading evaluation” was adopted to calculate the level and the grade of comprehensive benefit, by combining with cost-benefit analysis, fuzzy comprehensive evaluation, analytic hierarchy process, entropy weight method.Taking Jinhua City, Zhejiang Province as an example, a water rich area in south China, the evaluation system was applied to country, town and city research areas respectively.The results showed that the proposed evaluation system can reflect the objective reality, has strong universality, reliability and applicability, and can provide technical support for water saving evaluation in different regions or water systems.