Abstract: The present paper describes the isolation and purification of alkaline phosphatase (AKP) from the mantle of Anodonta woodiata (Heude), and its kinetic property is also examined. The alkaline phosphatase was partially purified from the mantle by homogenation, nbutanol extraction, salting-out and gel filtration with Sephadex G-100. Gained AKP product has a specific activity of 149.6 unit/mg AKP protein. The optimum pH value of the AKP product is 9.5 as hydrolysed in disodium phenyl phosphate and its optimum temperature is 40℃. The Michaelis-Menten constant (Km) is 0.57 mmol/L (on the disodium phenyl phosphate). The AKP was activated by Mg2+ and Ca2+ ions while inhibited by ions of Cu2+, Zn2+ and reagents of KH2PO4, EDTA and ME.