Abstract: The changes of different high pressure( HPP) conditions on microbial inactivation,p H,total volatile basic nitrogen( TVB- N),K value,the basic ingredients of oyster during chilled storage were investigated. The results showed that when the pressure conditions were 350 MPa for 10 min,the microbiological shelf- life of raw- eaten oyster could be extended to 7 days and the shelf- life of refrigeration could be extended to 14 days,when the pressure conditions reached to 450 MPa for 10 min,the microbiological shelf- life of raw- eaten oyster could be extended to 14 days and the shelf- life of refrigation could be extended to 21 days.When the pressure conditions reached 350 MPa for 10 min,and then storaged for fourteen days,or 450 MPa for 10 min then storage for twenty-one days,both of the TVB- N levels and K values met the standard of fresh oyster. The quality almost remained unchanged before and after HPP on oyster,and the nutritional value was maintained at the same time.