This study was examined digestive enzyme activity in the crystalline style of the three species of bivalves. Bivalves used in this study were Tegillarca granosa (n=61), Mytilus galloprovincialis (n=30) and Saxidomus purpuratus (n=30) and collected from southern coast of Korea on May 2010. Digestive enzymes activities in the crystalline style were assayed in spectrophotometer. Amylase and cellulase occupied approximately 90% of digestive enzyme in crystalline style of T. granosa, M. galloprovincialis, and S. purpuratus. And protease activity in crystalline style of T. granosa, M. galloprovincialis and S. purpuratus showed the lowest values to 0.02, 0 and 0.08%, respectively. Digestive enzyme activity in crystalline style of three species was measured in the order of cellulase ＞ amylase ＞ chitinase ＞ laminarase.