Abstract: In order to study the effects of Bacillus subtilis B7 on growth performance, feed protein digestibility in broilers. One hundred and eighty seven-day-old broilers were randomly divided into three groups with 4 replicates in each group, which were the control group （group C K ）,Bacillus s ubtilis 1 group （group Y 1 ）,Bacillus s ubtilis 2 group （group Y2 ）,the experimental period was 42 days. Study on the test set of material consumption, daily weight gain, feed conversion rate, gastric protein digestibility, ileal digestibility rate of protein. The results showed that, compared with CK group, Y2 group consumption was increased by 5.81%, weight gain was increased by 7.29%, feed conversion rate was reduced by 2.43%, which was a significantly difference（P〈0.05 ）. Furthermore, at the age of 14 days, group Y2 feeds gastric protein digestibility and ileal digestibility rate of protein were respectively increased by 28.07% and 21.29%, and the difference is significant （P〈0.05）. Broiler diets add the right amount of Bacillus subtilis can significantly improve the growth performance and feed utilization rate.