For the effective immobilization of urease on chitosan matrix with glutaraldehyde, optimal activation methods were studied, and its enzymatic properties was investigated. In the stability of enzyme the retained activity of the native urease was 55% after it was soaked at pH 7 for 10 hrs., while the retained activity of immobilized one was about 62% after soaked at pH 6.5-8.5 for the same time. After heat treatment at 60℃ for 10 hrs., the native urease lost the most of its activity, while immobilized urease retained 54% of its activity by the same treatment. The retained activity of immobilized urease did not decrease nearly when it was stored at room temperature for 25 days. From Linweaver-Burk plots, the V_(max) value of native urease was 66μM/ℓ and that of immobilized urease was 41μM/ℓ, while Km value 40mM/ℓ for both enzymes was unaltered.