In order to inquire into the effect of freeze on protein denaturation of shellfish food and improve the quality, take the Paphia undulata as an example, the effects of different freezing and frozen temperatures on salt-solubility and ATPase activity of myofibrillar protein in three kinds of the Paphia undulata＇s meat were studied in this paper. The results show that the final temperature of freezing have little effect on freeze denaturation of the Paphia undulata. However , the frozen stored temperature showed the freeze denaturation of protein evidently, the lower the frozen temperature, the less the extent of freeze denaturation; for three forms of the Paphia undulata, have more effect on the protein denaturation surimi and fragmentary meat as muscle structure destroyed than intact muscle tissue. It was also observed that the freezing denatureation of myofibrillar protein in shellfish meat could be efficiently reduced by addition of cryoprotectants especially in of surimi. Therefore application of addition cryoprotectants can effectively improve the quality of frozen shellfish.