Abstract: Most of the diseases caused by bacteria are cureed by antibiotics at present, but the misuse of antibacterial already lead to drug resistance, it's bad for the treatment of diseases and may be a hidden trouble to human health. It is prerequisite for us to look for the substitute for antibacterial; meanwhile probiotics, with its own characteristic, is becoming to play an important role in feed additive as the replacement of antibacterial, and it has uncountable effect on the development of stockbreeding. This paper stress on the choice of the strain,mechanism and the measurement of improvement of the probiotics.

Key words: probiotics; mechanism; application