Abstract: In order to make full use of protein,the Meretrix lusoria protein was separated in this paper,and four components of protein:the water-soluble protein,the salt-soluble protein,insoluble protein and non-protein nitrogen were obtained,and the general composition,the consist of amino acid,the SDS-PAGE electrophoresis and the thermal stability of the three protein were analyzed respectively. The results showed that the moisture,crude protein,ash content,total sugar and crude fat of fresh Meretrix lusoria were 84.9%,10.65%,1.20%,1.90%,0.31%,respectively,among the raw protein,the salt-soluble protein,water-soluble protein,insoluble protein and non-protein nitrogen were accounted for 32.94%,44.69%,16.49%,0.81%,respectively. There were various of amino acids in Meretrix lusoria,and the ratio of essential amino acids were appropriate,the contents of essential amino acid and flavor amino acid were high. The results of SDS-PAGE showed that the protein molecular weight of Meretrix lusoria was widespread,but there were some differences among the components:the weight of salt-soluble protein molecular was mainly distributed in 200~66.4 ku and 44.3~29.0 ku,the weight of water-soluble protein molecular was mainly concentrated in 66.4~25 ku,the weight of insoluble protein was mainly concentrated in the 200~44.3 ku. The DSC curves showed that the denaturation temperature of Meretrix lusoria protein was 49.5 ℃,the denaturation temperature of salt-soluble protein,water-soluble and insoluble protein were 41.7,38.8 and 43.2 ℃,respectively.