A total of 80 healthy 3-month-old Kangle yellow chicks were randomly divided into 4 groups with 5 replicates per group and 4 broilers per replicate. Broilers in the control(CON) group and stress(STR) group were fed a basal diet, broilers in yeast selenium(SY) and yeast selenium + stress (SY_STR) groups were fed the basal diet supplemented with 0.5 mg/kg yeast selenium. The adjustment period lasted for 7 days, and the experimental period lasted for 21 days. Broilers of groups STR and SY_STR were injected intraperitoneally with 15 mg/kg BW diquat at day 21, and broilers of groups CON and SY were injected intraperitoneally with an equivalent amount of sterile saline at day 21. At day 22, one chicken was randomly selected from each replicate, and the cecal content sample was collected for intestinal microflora analysis to investigate the effect of yeast selenium on cecal microbial diversity, microbiota structure, and species richness in oxidative stress broilers. The results showed as follows: 1) There was no significant difference in the α diversity index of the cecal microbiota among all groups (P>0.05). The β diversity analysis showed that the cecal microflora structure distribution of group STR was relatively scattered and had lower similarity compared with groups CON and SY_STR. 2) Compared with the group CON, the Firmicutes to Bacteroidota ratio (F/B) and the relative abundance of Enterococcus and Escherichia-Shigella in cecum of group STR were significantly increased (P<0.05), and the relative abundance of Parasutterella and Bilophila in cecum of group STR were significantly decreased (P<0.05). Compared with the group STR, the relative abundance of Bacteroidota in cecum of groups SY_STR and SY was significantly increased (P<0.05), and the F/B and the relative abundance of Firmicutes, Monoglobus and Escherichia-Shigella of groups SY_STR and SY were significantly decreased(P<0.05). Compared with the group STR, the relative abundance of norank_f_Muribaculaceae in cecum of group SY_STR was significantly increased (P<0.05), and the relative abundance of Enterococcus of group SY_STR was significantly decreased (P<0.05). 3) Compared with the group CON, the abundance of Clostridiales vadinBB60 group, Monoglobus and Erysipelaceae in cecum of group STR were significantly increased (P<0.05). Compared with the group STR, the abundance of Bacteroidota, Prevotellaceae_UCG-001, Alloprevotella and Paraprevotella were significantly increased (P<0.05). In conclusion, oxidative stress could cause changes in the cecal microbial diversity and microbiota structure of broilers; dietary supplemented with yeast selenium could intervenes changes of the diversity of cecal microbiota caused by oxidative stress in broilers.