The post-legislation assessment is an important approach to improve the water resource legal system, to enhance the legislation quality and effectiveness, and to strengthen the public awareness of participating into the legislation process in China. It should be carried out in line with the objective open and transparent, systematic and holistic, effectiveness-oriented principles. The assessment approaches including systematical analysis, comparative analysis and social investigation are adopted to evaluate the legality, rationality, compatibility, operability, conformity and effectiveness of water resources-related laws and regulations. In light of the current development of water resources-related legal system and the post-legislation assessment situations in China, the following suggestions are put forward: to improve the post-legislation assessment mechanism, to plan and implement the post-legislation assessment, and to give full play of the China's think tank of water resources in the the post-legislation assessment.