Natural chitin has the characteristics of high molecular weight， high crystallinity and difficult enzymatic hydrolysis， which greatly limits its development and application. In order to improve the utilization rate of chitin， commercial non-specific enzymes with high degradation ability and good economic benefits were screened in this study， and their enzymatic hydrolysis effects on chitin after three modification methods (ultra-micro grinding， high-pressure homogenization， ultra-micro grinding-high-pressure homogenization) were evaluated. Determine the best modification method， optimize enzymatic hydrolysis process and analyze enzymatic hydrolysis products. The results showed that among the seven non-specific enzymes， papain had the highest chitin degradation ability and the lowest cost. The combined pretreatment of ultra-micro grinding and high-pressure homogenization method made chitin have higher degradability， the optimum conditions for degradation of chitin by papain were temperature 50 ℃， pH 7.0， enzyme mass concentration 10 mg/mL， time 14 h. The results of thin layer chromatography showed that(GlcNAc)3-6 four degrees of polymerization of chitin oligosaccharides were produced at the initial stage of enzymatic hydrolysis(1 h)， which preliminarily proved that papain could break the β-1，4 glycosidic bond of chitin； the results of ion chromatography analysis showed that only GlcNAc and (GlcNAc)2 were found in the enzymolysis products after enzymolysis equilibrium (14 h)， and the mass concentrations were 22.26 mg/mL and 58.75 mg/mL， respectively.