The stabilization of Aspergillus sp. $alpha$-amylase was attained by modification with periodate-oxidized sol-uble starch. The pH stability of modified enzyme was increased at pH 3~4 and 9~11 in the presence of $alpha$-cyclodextrin($alpha$-CD) compared with that of native enzyme. Thermal stability of the modified enzyme was increased. After treatment at 6$0^{circ}C$ for 30min the activity remained 20% for the enzyme modified at pH 9.7 in the presence of $alpha$-CD and tested in the presence of $alpha$-CD 10% for the enzyme modified at pH 9.7 in the presence of $alpha$-CD 0% for the native enzyme. The native enzyme and modified enzyme showed one peak in HPLC. The substrate specificity of the modified enzyme was not changed in HPLC analysis of reaction product.