To explore the relationship between gut microbiota and growth of Chinese mitten crab(Eriocheir sinensis) at different water temperatures, the growth performance was tested and gut microbiota composition was analyzed by 16S rRNA high-throughput sequencing of this crab cultured at four water temperatures(26 ℃, 29 ℃, 32 ℃, and 35 ℃). The results showed that the molting times of Chinese mitten crab in four water temperature groups were 2, 2, 2 and 1 respectively, the survival rates were 82.81%, 84.38%, 87.50%, 25.00% respectively, the average molting interval shortened gradually with the increase of water temperature, the molting weight gain rate increased first and then decreased with the water temperature increasing, and the condition factor had no significant difference among different water temperatures (P>0.05). The sequencing results of the gut microbiota showed that 929, 744, 680 and 518 Operational Taxonomic Units(OTU) were obtained for the 26 ℃, 29 ℃, 32 ℃ and 35 ℃ water temperature groups, respectively.The α diversity results showed that the abundance and diversity of gut microbiota decreased with the increase of water temperature,and the results of β diversity analysis showed that there were significant differences (P<0.05) for the gut microbiota composition among the four water temperature groups. At the phylum level, the dominant gut microbiota for the four water temperature groups were Firmicutes, Bacteroidota and Proteobacteria, which accounted for 96.26% of the total microbiota, for Patescibacteria(0.92%)and Verrucomicrobia(0.35%)in the 26 ℃ group, Firmicutes(58.04%) and Actinobacteriota(3.44%)in the 29 ℃ group, and Bacteroidota(41.84%) in the 32 ℃ group,and the abundance of their gut microbiota was significantly higher than that of other water temperature groups (P<0.05).At the genus level, Gemmobacter(3.55%)in the 26 ℃ group,Citrobacter(3.56%)in the 29 ℃ group,Pragia(8.47%)in the 32 ℃ group, Psuedomonas(8.77%) in the 35 ℃ group, and the abundance of their gut microbiota was significantly higher than that of other water temperature groups (P<0.05). The results of this study indicated that the best water temperature should be about 30℃ for growth of Chinese mitten crab, the diversity and abundance of gut microbiota would decrease with the increase of water temperature, and under high temperature condition, some harmful flora, such as Campilobacterota and Malaciobacter, would increase and affect the molting and growth of Chinese mitten crabs.