The effects of high hydrostatic pressure (HHP) treatment on sea cucumber qualities, such as shelf-life, autoenzyme, total volatile basic nitrogen (TVB-N), mucopolysaccha ride and protein, were investigated experimentally. The shelf-life of sea cucumber was greatly prolonged by HHP treatment. High pressure treatment of sea cucumber significantly reduced the activity of autoenzyme at 550 MPa. The TVB-N content was 8.4 mg/100 g in the HHP-treated samples after 38 days' storage at 4 °C, while it had already reached 11.2 mg/100 g in the untreated ones after 5 days' storage under the same condition. The relative mucopolysaccharide content of the HHP-treated samples was 94.3%, while that of the heat-treated ones was only 35.5%. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Differential scanning calorimetric (DSC), ANS fluorescence probe method and fourier-transform infrared (FTIR) spectroscopy results indicated some changes in protein subunits, denaturation, surface hydrophobicity and secondary structure of sea cucumber protein. This study has provided complementary information of pressure-induced structural changes on both the molecular and the sub-molecular level of sea cucumber protein.