[Objective] To investigate the biological characteristics of Clostridium butyricum CB-7.[Method] The tests of acid-tolerance,bile salt-tolerance and high temperature-tolerance of Clostridium butyricum CB-7 were performed.In addition,the effects of Clostridium butyricum CB-7 on enteropathogenic bacteria like E.coli,Shigella and Salmonella as well as the intestinal beneficial bacteria like Lactobacillus acidophilus,Bifidobacterium,and Enterococcus faecalis.[Result] After culturing for 4 h at 37 ℃(pH 3.0),the survival rate of the Clostridium butyricum CB-7 was 90.0%;and the survival rate was 91.8% when they were cultured in medium containing 0.3% bile salt at 37 ℃ for 4 h.After water bathing at 90 ℃ for 10 min or 100 ℃ for 5 min,the survival rate of the Clostridium butyricum CB-7 was over 90.0%.The Clostridium butyricum CB-7 had great inhibition against E.coli,Shigella and Salmonella,and its extracts could greatly promote the growth of Lactobacillus acidophilus,Bifidobacterium,and Enterococcus faecalis.[Conclusion] The Clostridium butyricum CB-7 has strong resistance to acid,bile salt and high temperature,and strong inhibition against enteropathogenic bacteria,and it can also promote growth of intestinal beneficial bacteria.Thus,the Clostridium butyricum CB-7 is a feed strain with excellent performance.