This experiment was conducted to study the effect of xylanase in wheat-soybean meal diets on immune indices, intestinal morphology and intestinal flora of broilers. Four hundred and eighty one-day-old Avian broiler chicks were randomly divided into 4 treatments with 6 replicates and 20 broilers in each replicate, added with 0, 1 224, 2 449 and 3 673 IU/kg xylanase in the basal diet, respectively. The experiment lasted for 44 days. The results showed that: compared with control group, the spleen indices and erythrocyte rosette increased significantly in 1 224 and 2 449 IU/kg group on 22 days of age (P＜0.05), in 1 224 and 2 449 IU/kg group on 22 days of age, the duodenum indices increased significantly than control group and 3 673 IU/kg group (P＜0.05), the lamina propria mucosae thickness of duodenum and ileum increased significantly in 3 673 IU/kg group chickens at the age of 22 days of age than control group; the villus length of duodenum increased significantly in 2 449 IU/kg group chick at the age of 44 days of age than control group (P＜0.05), the erythrocyte rosette and the lymphocyte transformation ratio in 3 673 IU/kg group on 44 days of age increased significantly than control group (P＜0.05), the amount of Lactobacillus in ileum in 1 224 IU/kg group on 44 days of age increased significantly than other groups (P＜0.05). The results indicated that diets supplemented with 1 224 and 2 449 IU/kg xylanase in wheat-soybean meal diets could increase immune indices, improve intestinal morphology and flora of broiler.［Chinese Journal of Animal Nutrition, 2009，21(6):931-937］