In Vietnam, food poisoning and food tend to rise and epidemic becomes more and more complex. Besides Salmonella, Shigella, E. coli, one of the new cause is directly referred tousteria monocytogenes. To develop tools to rapidly detect the bacteria, in this study, monoclonal antibody was used in western blot assay. The results showed that monoclonal antibody detect bacteria at concentrations 10 exponent 5 CFU/ml, and express the potential for applications in diagnostic tools.