Glutaraldehyde was used to cross-link chitosan beads to immobilize the crude enzyme $eta$-glucosidase from Exiguobacterium sp. DAU5. The conditions for preparing cross-linking chitosan beads and immobilization such as concentration of glutaradehyde, cross-linking time, immobilization pH and time were optimized. The chitosan beads were cross-linked with 1.5% glutaraldehyde for 1.5 hr. The immobilized $eta$-glucosidase had an overall yield of 20% and specific activity of 5.22 U/g. The optimized pH and temperature were 9.0 and $55^{circ}C$, respectively. More than 80% of its activity at pH 7.0-10.0, 80% at $40^{circ}C$ for 2 hr and 48% at $50^{circ}C$ for 1 hr, were retained. However, the immobilization product showed higher pH and thermal stabilities than free enzymes. It also showed high hydrolyzing activity on soybean isoflavone glycoside linkage. These results suggest the broad application prospects of immobilization enzymes.