Abstract: 【Objective】To investigate the effects of different levels of Astragalus polysaccharides on the growth performance, serum biochemical indexes and intestinal flora structure of Mauremys mutica, with a view to providing theoretical basis for the application of Astragalus polysaccharides in the diets of M. mutica and the healthy breeding of M. mutica.【Method】M. mutica with an initial average body weight of 128.36±1.80 g were randomly divided into five groups, and fed isonitrogenous and isofat diets containing 0(M0), 0.25%(M25), 0.50%(M50), 0.75%(M75), and 1.00%(M100) Astragalus polysaccharides, with three replicates of 10 M. mutica in each group. After feeding for 60 d, the growth performance indexes and serum biochemical indexes were measured, and the structure of intestinal flora was analyzed by highthroughput sequencing. 【Result】The results of growth performance analysis showed that the weight gain rate and specific growth rate of M. mutica in the M25, M50 and M75 groups were significantly higher than those in the M0 group(P<0.05, the same below), and the feed coefficients were significantly lower than those in the M0 group, among which the M50 group had the highest weight gain rate and specific growth rate, and the lowest feed coefficient, and the daily growth rates of the dorsal carapace length, dorsal carapace width and dorsal carapace height of M. mutica in the M25, M50, M75 and M100 groups had no significant difference from those of the M0 group(P>0.05, the same below). The results of serum biochemical indexes showed that the activities of alkaline phosphatase and superoxide dismutase in M25, M50 and M75 groups were significantly higher than that of M0 group, and the activities of catalase in M50, M75 and M100 groups were significantly higher than that of M0 group; and the contents of malondialdehyde in M25, M50 and M75 groups were significantly lower. The results of intestinal flora analysis showed that the community richness indexes(Sobs index and ACE index) were significantly higher in M25 group than in M0 group, and the community diversity indexes(Shannon index and Simpson index) were not significantly different from those of M0 group. The differences of Sobs index, Chao1 index, ACE index, Shannon index and Simpson index were not significantly different from those of M0 group in M50, M75 and M100 groups. At the phylum level, the top 3 groups in terms of relative abundance were Firmicutes, Bacteroidetes and Proteobacteria, and 0.25%-1.00% of Astragalus polysaccharides did not significantly affect the composition of intestinal flora at the phylum level. At the genus level, the relative abundance of Ruminococcus 1 in the M50 group and Halomonas in the M75 group increased significantly; the addition of 0.25% and 1.00% of Astragalus polysaccharide had no significant effect on the composition of intestinal flora at the genus level. 【Conclusion】Addition of appropriate amount of Astragalus polysaccharide to feed can effectively promote the growth of M. mutica, improve antioxidant capacity and improve the structure of intestinal flora. It is recommended to add 0.50% of Astragalus polysaccharide to the feed.