Oxidation effect of ?OH on sensitive amino acids in myofibrillar protein(MP) was studied based on Fe3+-H2O2-Vc oxidation system.The results showed that the oxidation effect of ?OH on amino acids in MP was selective.Among these amino acids，aspartic acid(Asp)，glycine(Gly) and leucine(Leu) were insensitive to oxidation，in which their contents did not change significantly after being oxidized.But cysteine(Cys)，methinnine(Met) and tyrosine(Tyr) were sensitive to oxidation，and their contents reduced gradually with the increase of H2O2 concentration，which resulted in the increase of ?OH generated in the Fe3+-H2O2-Vc oxidation system.The results also showed that the oxidation of MP could lead to the contents of protein carbonyl and bityrosine increasing，and sulfydryl decreasing.Further study showed that amino acids oxidation was concentration-dependent.The degree of oxidation increased with concentration of H2O2，and after being oxidized with 20.0 mmol/L H2O2 for 24 h，the contents of Cys，Met and Tyr decreased 13.3%，11.6% and 20.5%，respectively，compared with the control sample.Therefore，the oxidation-mediated structure changes of sensitive amino acids containing reactive groups were the major cause of protein oxidation.