In order to find effective microecological preparations for preventing necrotic enteritis （NE） in chickens in this study， a total of 120 one-day-old 817 chickens were randomly divided into four treatment groups. Control group and NE group （broiler model of NE established by infecting with Clostridium perfringens type G） were fed a basal diet. Probiotic group （Prob1） was fed a basal diet supplemented with 0.2% microbial agent 1， and probiotic group （Prob2） was fed a basal diet supplemented with 0.2% microbial agent 2. On days 14 to 16， broilers in Prob1， Prob2 and NE groups were treated with Clostridium perfringens （CP） by continuous gavage. The preventive effects of the two different Bacillus subtilis compound microbial preparations on NE of broilers were evaluated in the 23-day trial period. The results showed that， on day 17， the body weight of broilers in the NE group was lower than that of the control group. However， broilers in the Prob1 and Prob2 groups had a higher body weight at the 17th and 23rd days of the experiment compared to the NE group. The jejunal epithelial cells of broilers in the NE group were necrotic and exfoliated， with a shorter villus， deeper crypt， and smaller villus length and villus crypt ratio compared to the NE group treated with B. subtilis compound microbial preparation. The activities of T-SOD， T-AOC and AKP in the jejunal mucosa of broilers in the NE group were lower than those in the Control group. However， on day 17， the T-AOC and AKP activities in the jejunal mucosa of broilers in the Prob1 and Prob2 groups were significantly higher than those in the NE group， and the T-SOD activity of jejunal mucosa of broilers in Prob1 group was significantly higher than that in NE group. On day 23， the activities of T-SOD， T-AOC and AKP in jejunal mucosa of broilers in the Prob1 and Prob2 groups were higher than those in the NE group， and there were no significant differences. The content of MDA in jejunal mucosa of broilers in the NE group was higher than that in the control group， and the content of MDA in the Prob1 and Prob2 groups was lower than that in the NE group at the 17th and 23rd days. The gene expressions of intestinal tight junction protein CLDN1 and ZO-2 in the NE group were lower than those in the Control group， and there were significant differences on day 17 of the experiment. On the 17th and 23rd days of the experiment， expressions of the intestinal tight junction protein CLDN1 and ZO-2 genes in the Prob1 and Prob2 groups were higher than those in the NE group， and the expressions of ZO-1 gene in the Prob1 and Prob2 groups were significantly higher than those in the NE group. The results showed that adding B. subtilis compound microbial preparation to the diet could improve the growth and development of chickens with necrotizing enteritis， increase the antioxidant capacity and intestinal tight junction protein gene expression of broilers， and B. subtilis compound microbial preparation 1 had a better preventive effect on chicken necrotic enteritis.