Abstract: The study was conducted to investigate the preservation effect and enzymatic mechanism of starvation stresses in Penaeus vannamei.Shrimps were exposed to starvation stresses and then preserved at 4℃.In order to evaluate the effect of starvation stresses on quality changes of shrimps, sensory evaluation, biochemical indicator and total bacteria count were determined, and the influences of starvation on the activities of polyphenol oxidase and protease were studied. The results showed that the group with starvation treatment for 4d could restrain the increase of p H and TVB- N value, reduce the change of total bacteria counts and keep the sensory quality of shrimp significantly.Compared with control group, the endogenous protease activity of the group with starvation stress for 4d were reduced by 41.2%, but there were no significant differences ( p > 0.05) in the impact on phenol oxidase activities.The group with starvation stress for 4d had good preservation effect and could prolong the shelf- life for 1²d, the mechanism was to inhibit the activity of endogenous protease and delay the quality decline in shrimp.