In this study, polyvinyl alcohol (PVA) was used as crosslinking agent with glutaraldehyde, which was polymerized with polyvinyl alcohol and reacted with epichlorohydrin for immobilization of epoxy group. The product can be used as enzyme immobilization carrier. The epoxy immobilization conditions of the cross-linked PVA and enzyme immobilization conditions were investigated. The immobilization can stabilize the enzyme and ensured high mechanical and chemical stability of the biocatalyst，which could be used many times for sodium phytate hydrolysis. Various characteristics of immobilized phytase such as optimum thermal storage stability and pH, were evaluated. The optimal pH value of free and immobilized phytase were 5.5 and 7.0, respective, and the optimal thermal free phytase was 55℃, whereas that of immobilized phytase was 70℃. The operational, pH value, and thermal stabilities of the enzyme were increased by immobilization.