Abstract: Physicochemical properties of myofibrillar proteins in Euphausia Superba was investigated following extraction of oil with supercritical CO2 in order to provide basic information for food process.The lipids of Euphausia Superba was extracted at 15~25 MPa,35 ~ 55 ℃,2 h and 15 MPa,35 ℃,1 ~ 3 h. Sulphydryl content,Ca2 +- ATPase activity,surface hydrophobicity and SDS- PAGE pattern were measured after extraction to study the changes in myofibrillar proteins.Total sulphydryl content and Ca2 +- ATPase activity decreased with pressure,temperature and time while surface hydrophobicity increased after extraction. The changes in total sulphydryl content and Ca2 +-ATPase activity mainly occurred during the first hour,however,surface hydrophobicity increased most at 1 ~ 2 h.SDS- PAGE pattern showed there were slight changes in protein bands,which indicated the structure of myofibrillar proteins varied after supercritical CO2 extraction,thus some new bonds formed.After supercritical CO2 extraction,the oxidized sulphydryl groups,formed disulfide bonds,increase in surface hydrophobicity and formation of some new bonds all improved the emulsifying and gel properties of proteins,which was very important to the application of the Euphausia Superba.