Abstract: The interplay between intestinal microorganism and their host has received extensive scientific attention, however, there is no study about the response of intestinal microorganism of the Chinese mitten crab in the hunger state. In the present study, 16S rRNA sequencing was used to investigate intestinal microorganism in Chinese mitten crab during the period of starvation and refeeding. The results showed that the Alpha diversity index of the intestinal microorganisms decreased by starvation, and re-feeding did not change the descending trend of the intestinal microbial diversity index. Besides, there was no significant difference comparing to the control group (P>0.05). In terms of the bacterial phyla composition, starvation gradually increased the proportions of the Proteobacteria, Firmicutes and Bacteroidetes and reduced the proportion of Tenericutes. Re-feeding restored Proteobacteria, Firmicutes, Bacteroidetes and Tenericutes to the level of control group. By comparing different strains under different conditions, 8 strains with significant differences (P<0.05) were sifted at the family and genus level. Among them, Candidatus bacilloplasma was characterized by high abundance of bacteria and significant response to starvation and refeeding, and its specific function of the flora needs further investigation. This study first reported the changes of intestinal flora of the crabs after starvation and refeeding, which could provide basic knowledge for the further exploration of the specific functions of the flora.