Combining the parallel coordinate method of information visualization with the marine environmental quality visualization analysis,taking sea water quality index as class standard and the improvement of water quality index and the intuitive characteristic of index level,the paper first all established the parallel coordinate method of visualization analysis for the marine environmental quality.It set up the detailed and systematic assessment method and procedure for water environmental quality by combining set pair analysis method with cloud theory. The method has no only the advantages of concision, easy-operation and high precision of set pair analysis method but the randomness and ambiguity of assessment indexes' membership can be reflected in the assessment procedure by using cloud theory.This paper used the combination of parallel coordinate, the coupled assessment method of cloud theory and set pair analysis,and applied to analyze and evaluate the water environmental quality near the shore of Tianjin district in recent ten years.The result showed that the water environmental quality is poor and the eutrophication phenomenon is serious by nitrogen and phosphate near the shore district of Tianjin. The visualization analysis method with parallel coordinate has some advantages of concision and perceptual intuition. The method collected the advantages of two methods and can be applied to water environmental quality assessment accurately and reliably.