To explore the nutrient quality differences and status of gut microbiota in Chinese mitten handed crab(Eriocheir sinensis)from the cold regions of northern China after a long period of natural overwintering in low-tem-perature environments,tissue indicators,muscle nutritional components,mineral elements,and fatty acid content were analyzed in the crab with body weight from 104 g to 140 g,and the composition of gut microbiota in the crabs collected from Xiangyang Lake(47° 9′36″N,88° 7′12″E)and(47°8′24″N,88°10′12″E)of Xinjiang Produc-tion and Construction Corps before and after overwintering by high-throughput sequencing technology of the 16S rRNA.The results showed that the condition factor and hepatopancreas index were found to be significantly de-creased in the female crab(P<0.05),while the condition factor and gonadosomatic index to be significantly in-creased in the male crab(P<0.05),with significant change in the contents of mineral elements Na,K,Mn,Fe and Cu in different trends(P<0.05),and significant increase in the content of unsaturated fatty acidsy(P<0.05)after natural overwintering in the lake.The diversity and abundance of the gut microbiota were shown to be de-creased in crab after overwintering,with noticeable changes in microbial composition.Firmicutes(71.14%),Bacteroidota(15.19%),and Proteobacteria(9.69%)were the dominant phyla before overwintering,and Pro-teobacteria(52.79%),Firmicutes(37.10%),and Bacteroidota(4.35%)after overwintering.The abundance of the genus Psychrobacter within Proteobacteria was increased significantly from 0.10%before overwintering to 43.75%,becoming the dominant genus,after overwintering.The findings indicate that the quality of crab does not significantly decline after a long period of natural overwintering in Xinjiang Uygur Autonomous Region,and some nutritional indicators are better than before overwintering,and the structure of gut microbiota also undergoes adap-tive adjustments.These findings provide basis for exploring new cultures and sales models of E.sinensis in this re-gion.