Abstract: Clostridium b utyricum has its particular biological function. It can adjust the balance of intestinal flora,activate the immunity system, enhance the body immunity, inhibit tumors ,producing probiotics, promote the growth and recovery of intestinal epithelial cells, produce many kinds of enzymes, improve the feed conversion rate,promote animal growth,etc. C. butyricum showed strong tolerances to high temperature, acid and bile, so it can better adapt to farms and its storage environment compared with lactic acid bacteria and yeast strain. C. butyricum can easily colonize in the animal intestines and play its roles. Therefore C. butyricum has wide application prospects. Nowadays C. butyricum has been widely used in animal production. And it would become the preferred species of animal micro-ecological agents in the future.