Abstract: The montmorillonite is a good absorptive and is used as a carrier for glucoamylase immobilization by absorption. The results here show that the activity of immobilized enzyme is 3442u per gram；the optimal pH value of immobilized enzyme is 4.8, 0.2 higher than that of free enzyme；the optimal temperature is 60℃, 5℃ higher than free one； the half-life of immobilized enzyme is 12 days; and the Michaelis constant of immobilized enzyme is Km=14.3g/L, which is 1.47 times as the free one.