Abstract: Three amylases were purified to electrophoretic homogeneity from viscera of hard clam Meretrix lusoria by ammonium sulfate fractionation, Sepharose 6B, DEAE‐Sephadex A‐50, Sephadex G‐200 and PBE 94 chromatographies. The purified amylases had molecular masses of 49.6, 58.7 and 100 kDa and were designated AI‐1, AI‐2 and AII, respectively. Both AI‐1 and AI‐2 could digest amylose into glucose and maltose, while AII could digest amylose and pullulan into glucose. The optimal pH and temperatures for AI‐1, AI‐2 and AII were 7.0, 7.5 and 7.5, and 40, 50 and 50°C, respectively. According to the substrate specificity, the purified AI‐1 and AI‐2 were considered to be multifunctional exo‐ and endo‐types of α‐amylase‐like enzymes, while AII was exo‐type γ‐amylase‐like enzyme. They were Ca2+‐independent enzymes.