Abstract: In this paper,hydroxyl radical oxidation system was used to simulate oxidation,the changes carbonyl content,surface hydrophobicity,active hydrophobic content,solubility and water retention of myofibrillar protein in cultured Pseudosciaena crocea under different oxidation time (1,3,5 h) and oxidant concentrations (0,0.1,1,5,10,20 mmol/L H₂O₂) were explored. The results showed that hydroxyl radical oxidation system could cause MPI structure changes in Pseudosciaena crocea. With the increase of concentration and time,the carbonyl content increased and the surface hydrophilicity increased slightly. When the oxidation time was 1 h,the contents of active sulfhydryl group decreased with the increasing of H₂O₂ concentration. When the oxidation time was 1,3 h,the solubility decreased obviously after H₂O₂ treatment. At 5 h,the solubility increased first and then decreased. When the oxidation time was 5 h,the water holding capacity decreased with the increasing of H₂O₂ concentration. SDS gel electrophoresis revealed that protein oxidation could lead to cross-linking between proteins. These changes indicated that the free radical oxidation system had a very important effect on the structure of myofibrillar protein in Pseudosciaena crocea.