In order to evaluate the happiness level of regional rivers, 21 indicators are selected from seven aspects including flood control and safety, high quality water resources, healthy water ecology, livable water environment, advanced water culture, green aquaculture and civilized water management, with which a regional river happiness evaluation system was constructed and then introduced to the evaluation model. In this model, the subjective and objective weights of the indicators are determined by cloud model and entropy method, and an improved grey TOPSIS model is established based on the combination of TOPSIS and grey relational analysis to calculate the comprehensive closeness of multiple indicators and research objects, so as to estimate their individual degree of happiness. This model was then applied to the evaluation of the typical rivers in Changzhutan region and seven cities in the periphery. The evaluation results show that the river happiness varies greatly in different regions, yet the problems reflected by some indicators are universal and are consistent with the actual situation, indicating that the proposed evaluation model is feasible. The evaluation results and recommendations can provide some reference for the cultivation of happy river in Changzhutan region.