Abstract:In order to determine the main bacteriostatic substances produced by the lactic acid bacteria isolated from the intestinal tract of the sea fish，sixteen strains of peroxidase-negative and Gram-positive bacilli were screened from 41 strains isolated from the four marine fish intestines，and were initially identified as Lactobacillus. Using Escherichia coli as indicator bacteria，the antagonistic effect of 16 strains on Escherichia coli was studied by Oxford cup agar diffusion method. Six strains of bacteria with strong antibacterial activity were screened. The inhibition zone diameters of the strains were 13.73，14.77，13.71，12.84，13.63 mm and 13.65 mm，respectively. 6 strains were numbered S2-4，S2-6，Y3-1，H2-4，B2-4 and B2-10. Salmonella，Staphylococcus aureus，Listeria monocytogenes，Vibrio parahemolyticus and Shigella Castellani were used as the indicator bacteria to research the inhibitory effects of referred 6 strains. The result demonstrated that all of the 6 screened strains showed antimicrobial activities in different degree，which the inhibitory zone diameters were more than 14 mm and the inhibitory effects of S2-6 and Y3-1 were the most significant.The results showed that antibacterial substances of the 6 strains would be acid or bacteriocin.The strain B2-4，H2-4 and S2-4 were identified as Lactobacillus sakei by the analysis of 16S rDNA sequence，while the strain S2-6 and Y3-1 were identified as Lactobacillus plantarum.