A bacteriocin-producing lactic acid bacteria strain designated as NLB-3 was isolated from natural fermentation broth of a soybean plant. By excluding the disturbances of organic acids and H₂O₂ to antibacterial activity of indicator bacteria, and after the fermentation broth protein stability analysis, the antibacterial substance was determined as bacteriocin. On the basis of the colonies, cells morphology, dissolved calcium circle, physiological and biochemical characteristics, strain NLB-3 was preliminary identified as Lactobacillus sp.. The biological characteristics of strain NLB-3 showed that, its optimum growth temperature was at 35 ℃, after 16 hours fermentation, the pH value reached 3.45 and it had a wider range of salt tolerance, but when the NaCl concentration was greater than 10%, and the growth of this strain was significantly inhibited.