Abstract: Using oyster as the raw material,the protein in oyster was classified by Osborne method,and the oyster protein was separated and extracted by isoelectric precipitation,while the molecular mass distribution was analyzed by SDS-PAGE.The results showed that the oyster protein component content was salt soluble protein>alkaline solution>water soluble protein>alcohol soluble protein.The optimal conditions for protein extraction were room temperature,alkaline solution conditions pH 12,1.0 h,acid precipitation conditions pH 4.0,under which the protein extraction rate was 65.6% and the purity was 84.3%(dry basis).SDS-PAGE electrophoresis showed that the water-soluble protein had obvious bands around 44.3 kDa and 14.3 kDa in the samples treated with β-mercaptoethanol;the salt soluble protein had obvious bands around 45 kDa and 20.1 kDa;alkaline solution appeared in three bands at 200,44.3 and 14.3 kDa;and the protein sample prepared by the pH adjustment method showed a distinct band at 44.3 kDa.In the samples without β-mercaptoethanol treatment,the salt soluble protein appeared in the band around 29.0 kDa and 14.3 kDa,while the protein sample prepared by the pH adjustment was at 97.2 kDa.There were distinct protein bands.The research structure provides a theoretical basis for the further development and utilization of oyster protein.