Supercritical fluid technologies have found applications in a wide range of areas and have been explored for use in the inactivation of bacteria.However,the mechanism for cell inactivation is not yet understood.The inactivation of E.coli by supercritical CO2 through the method of plate count to measure the number of E.coli was studied in the paper,and the influences of supercritical CO2 on the total protein and soluble protein of E.coli through SDS-PAGE analysis was studied too.