Abstract: The inhibitory effect of Lactobacillus plantarum DL3 on Pseudomonas aeruginosa and Shewanella putrefaciens in grass carp slices was studied,and the antibacterial and fresh-keeping effects were verified by sensory evaluation,microbial indicators and physicochemical indicators. The results showed that the strain DL3 treatment group could effectively maintain the sensory quality of grass carp slices under cold storage conditions at 4℃. Compared with the control group,the number of bacteria in P. aeruginosa and S. putrefaciens in the grass carp were reduced by 2.06 and 0.97 lg CFU/g,respectively,which effectively inhibited the growth and reproduction of spoilage organism and P. aeruginosa in the grass carp slices. The pH of the fish fillet showed a trend of "V" change,which indicated that the added strain DL3 had a retarding effect on pH rise. The TVB-N value of the strain treated with the strain DL3 alone was 18 mg/100 g,which effectively controlled the degradation of the protein. It was showed that strain DL3 could be used as a biological preservative for freshwater fish and its products,and had certain application value for controlling the corruption of aquatic products.