The Antarctic krill carboxymethyl chitosan(CMC) made in the laboratory was selected as the material in this study. The CMC with different mass fractions(0.5%, 1.0%, 1.5%) was used to coat the Macrobrachium rosenbergii, without soaking CMC as the control, which kept fresh for 7 days at (4±1) ℃. The quality changes of Macrobrachium rosenbergii during the fresh-keeping period were evaluated by TVB-N(total volatile base nitrogen) value, pH, TBA(thiobarbituric acid) value, TVC(total number of colonies), K value and sensory scores. The results showed that after 1 day of storage, the TVB-N values, TBA values, TVC and K values of CMC groups were lower than those of control group during the same storage time, while sensory scores were higher than that of control group. At the same storage time during the later stage(5-7 d), the pH of CMC groups were lower than that of the control group. During the whole storage period, except for a few time points, the TVB-N value, pH value, TBA value, TVC and K value of 1.0% CMC group were lower to those of 0.5% CMC group and 1.5% CMC group, while the sensory score was higher than those of 0.5% and 1.5% CMC group. In conclusion, 1.0% CMC had a better fresh-keeping effect on Macrobrachium rosenbergii, which could effectively reduce microorganisms quantity and enzyme activity in Macrobrachium rosenbergii, inhibit protein decomposition and fat oxidation in the shrimp, and extend the shelf life of Macrobrachium rosenbergii.