Phytases are enzymes capable of hydrolyzing phytic acid(orphytate) to less-phosphorylated myo-inositol derivates and inorganic phosphate. Phytases are new enzyme preparation. The addition of phytase to feed and food can resolve the antinutrition of phytic acid and increase the bioavailablity of protein and minerals. The progresses in the recent studies related to the molecular architecture, the functional mechanism, the biologic characterizations, and the structure of its gene of phytase were reviewed.