A 56-day feed trial was carried out to investigate the effects of chitosan oligosaccharide (COS) and/or mycotoxin adsorbent on the intestinal mucosa structure and gut flora of . Four isonitrogenous and homoenergetic diets were prepared on the basal diet by adding 0 mg/kg (COS or mycotoxin adsorbent), 250 mg/kg COS, 2500 mg/kg mycotoxin adsorbent, 250 mg/kg COS+2500 mg/kg mycotoxin adsorbent, and named as C0, C0.25, M2.5 and C0.25+M2.5, respectively. The with an initial weight of 0.23±0.02 g were randomly assigned into 4 groups. The results showed as follows:the combined use of COS and mycotoxin adsorbent helped improve the index of intestinal morphology, group C0.25+M2.5 showed significant difference (<0.05) about the intestinal villus length with group C0, C0.25, and showed significant difference (<0.05) about the intestinal width with group M2.5, moreover, the thickness of muscle layer in this group was significantly higher than others (>0.05) about effective OTUs (Operational taxonomic unit) among groups; index of Observed species and Shannon index and PD (Phylogenetic diversity whole tree) value in group C0.25+M2.5 were significantly lower (<0.05) than those of group M2.5 and remarkably higher than group C0.25, but showed no significant difference (>0.05) with group C0. At the phylum level, microbial floras detected in this experiment mainly belonged to Proteobacteria, Firmicutes or Bacteroidetes, group C0.25+M2.5 showed the minimum of Proteobacteria and the maximum of Firmicutes, group C0 showed the minimum of Bacteroidetes. At the level of genus, species mainly detected were and in group C0.25+M2.5 were lower than that of control group. Group C0.25+M2.5 showed the lowest content of Photobacterium and the highest content of Pseudoalteromonas. It can be concluded that adding COS and mycotoxin adsorbent in diets had no effect of on microbial floras, nevertheless, optimized the index of intestinal morphology and the structure of gut flora, but can promoted intestinal health, and is better than a single adding groups.