Abstract: This paper described the enzymatic hydrolysis of chitosan by papain and cellulase. The effects of temperature, pH, substrate concentrations, the ratio of emzyme to substrate and the proportion of compound enzyme on the degradation of chitosan were investigated, and the infrared spectrum was used to analyse the structure of degradation products. The results showed that the optimal pH,temperature, concentration of substrate, the ratio of emzyme to substrate and the proportion of compound enzyme were pH 5.0, 45℃, 12 g/L,6% and 2:1 respectively. Infrared analysis indicated that the chemical structure of chitosan was not changed after enzymolysis.