Abstract: A comprehensive evaluation system of vessel congestion in the Three Gorges Dam area is proposed in order to effectively and quantitatively evaluates the congestion degree of ships passing the Three Gorges Dam.The entropy method is improved and applied to determine the index weights of vessel congestion evaluation.The method consists of subjective weights by expert surveys and objective weights through statistical analysis of actual data.Therefore, limits of subjectivity and insufficiency of data can be effectively overcome.The ratio between the subjective and objective weight is found as 0.624∶0.376.In the presence of deterministic and uncertain characteristics of the evaluation indices, an improved cloud model is developed.The eigenvalue parameters are replaced by normal elements, on basis of which the cloud correlations between matter elements and a standard cloud matter model are computed.The proposed model is applied to evaluate the degree of vessel congestion in the Three Gorges Dam area for the year 2015.The evaluation degree is known as [0.126, 0.221, 0.172, 0.325, 0.156] and the congestion degree is 4.The presented findings are generally consistent with the actual situations.