Abstract: Objective:19 strains of intestinal bacteria from the elderly and 8 strains from common health people as the experiment object, screening had hingh efficient antibacterial strain and determining the antibacterial effect of suspicious substance. Methods:Using filter paper method for screening high antibacterial activity strains, at the same time by different treatment (temperature, acidity, concentration of the enzyme) determination the changes of antibacterial activity, finally determination of the content of organic acid by using high performance liquid chromatography method and determination the inhibiting ability of organic acids. Results:From 27 strains breeding of a three strain with broad-spectrum, highly efficient inhibition effect of lactic acid bacteria, studing the bacteriostatic compositions were three strains of lactic acid bacteria, finally found the antibacterial effect of material were bacteriocins and short chain organic acid. Conclusion:27 bacterial strains had the ability of antibacterial, but the ability of antibacterial of bacterial strains separated from dung of long-lived old people was stronger than the general people’s. We conducted antibacterial test by using these metabolites of lactobacillus-organic acid (Lactic acid, butyric acid and acetic acid) and bacteriocins (stable to temperature and sensitive to protease) as main substrate. The result showed the two kinds of substances had significantly antibacterial effects at the low pH condition, which was essential condition to antibacterial activity.