Abstract: Chitooligosaccharides were prepared by hydrogen peroxide method, with Q TRAP LC/MS/MS System to determine chitooligosaccharides’ average molecular weight and on the inhibitive effects of chitooligosaccharides on four species intestinal causative microorganism were studied. The inhibitive function is obvious compared with the blank. The results showed that the lowest concentration of chitooligosaccharides inhibiting Esaherichiacoli and Staphylococcusaureus is 0.3%, and the lowest concentration of chitooligosaccharides inhibiting S.paratyphi A and Shigella-sonnei is 0.1%. With the increasing of concentration of chitooligosaccharides, the inhibitive function is enhanced. The results showed that the chitooligosaccharides has good inhibitive effect on intestinal causative microorganism.

Key words: chitooligosaccharides, intestinal causat ive microorganism, antimicrobial activity