Combining the concept of Happy River with the regional integration development strategy of the Yangtze River Delta, a hierarchy evaluation system of Happy River in the Yangtze River Delta including 24 indicators was established from natural system, human social system and human-water relationship system. Introducing the hierarchy of needs theory, the hierarchy evaluation level of Happy River was divided into Basic I, Basic Ⅱ, Upgrade I, Upgrade Ⅱ, and Happiness level. Entropy weight and matter element method was utilized to build the hierarchy evaluation model of Happy River in the Yangtze River Delta and the Happy Rivers level of three provinces and one city in the Yangtze River Delta in 2018 was evaluated. The results show that three provinces and one city are all in intermediate state of transformation. Among them, Jiangsu Province is transforming to Upgrade I level, Zhejiang Province and Anhui Province are transforming to Upgrade Ⅱ level, and Shanghai City is transforming to Happiness level. The results illustrate that the overall level of Happy River in the region is at a relatively high level, but the stability is poor.