The experiment was conducted to study the effects of Bacillus licheniformis on intestinal structure and cecal gut microflora in Mayu broiler chickens. Three hundred one-day-old broiler chickens were randomly divided into 5 groups with 4 replicates each and 15 broilers in each replicate. Group Ⅰwas fed with the basal diet as the control group without any antibiotics; the experimental groups (groups Ⅱ, Ⅲ, Ⅳ) were fed with the basal diet supplemented with 50, 100 and 200 mg/kg of Bacillus licheniformis, respectively; the group Ⅴ was fed with the basal diet supplemented with 30 mg/kg Bacitracin zinc and 6 mg/kg Kangdisu sulfas. The experiment lasted for 70 days. The results indicated that: at 28 days of age, the villous height (VH) of group Ⅱ was 11.35% higher than that of group Ⅰ, 5.81% higher than that of group Ⅴ,the quantity of Escherichia coli in cecum of group Ⅱ was lower than that of group Ⅰ (P<0.05), the quantity of Lactobacillus and Bacillus bifidus of group Ⅱ were higher than that of group Ⅴ (P<0.05); at 70 days of age, the cryptae depth (CD) of groups Ⅲ and Ⅳ were 25.67%, 24.72% lower than that of groupⅠ, the differences were significantly (P＜0.05), the quantity of Escherichia coli in cecum of experimental groups was lower than that of group Ⅰ (P<0.05), the quantity of Lactobacillus and Bacillus bifidus of group Ⅳ was higher than that of group Ⅴ (P<0.05). In conclusion, dietary Bacillus licheniformis supplementation was beneficial to the development of intestinal and the balance of cecum microflora, dietary Bacillus licheniformis level (50 mg/kg in early time and 200 mg/kg in latter time) could optimize intestinal structure and inhibit the growth of harmful bacteria in the cecum significantly.［Chinese Journal of Animal Nutrition, 2010，22（3）:757-761］