Abstract: The aim of this study was to investigate the effect of CO₂-cold seawater pretreatment and modified atmosphere packaging on the quality of Litopenaeus vannamei,under refrigeration storage at 4 ℃. Six treatments were carried out,air(CK1),vacuum(CK2),100% CO₂(QT1),40% CO₂/60% N₂(QT2),85% CO₂/5% O₂/10% N₂(QT3),40% CO₂/30% O₂/30% N₂(QT4). The microorganisms,pH,total volatile basic nitrogen,polyphenoloxidase activity,and texture were monitored and compared. The total bacterial count,pH,and total volatile basic nitrogen displayed a positive correlation and increased along with the storage time. Polyphenoloxidase activity and shering force dropped gradually. Three treatments,including QT1,QT2 and QT3,retarded the values of the total bacterial count and total volatile basic nitrogen. According to the results of polyphenoloxidase activity determination,modified atmosphere packaging of QT2 and QT3 had a better browning inhibitiong effect. The shelf-life of these experimental groups was prolonged for another 2~3 days.