The invention discloses an enzymatic production technology of chitosan oligosaccharide. The technology comprises steps as follows: a, chitosan is added to an acetate solution, and a chitosan solution is prepared; b, a hydrogen peroxide solution is added to the chitosan solution and stirred uniformly, a mixed solution is subjected to a degradation reaction, and a degraded solution is obtained after degradation; c, the degraded solution is cooled to the room temperature, pH value is regulated to 6.2-6.5, then beta-glucosidase is added for primary enzymolysis, and a primary enzymatic hydrolysate is obtained; d, alpha-1, 4-glucan glucohydrolace is added to the primary enzymatic hydrolysate for secondary enzymolysis, and a secondary enzymatic hydrolysate is obtained; e, pH value of the secondary enzymatic hydrolysate is regulated to 6-6.5, the secondary enzymatic hydrolysate is subjected to rough filtration, ultrafiltration, nanofiltration, spray drying and sterilization sequentially, and a finished chitosan oligosaccharide product is obtained. According to the enzymatic production technology of chitosan oligosaccharide, the yield of chitosan oligosaccharide is greatly increased, molecular weight of the finally prepared chitosan oligosaccharide product can be smaller than 1500, the size is relatively uniform, and besides, the product contains no monosaccharide, therefore, the quality of the chitosan oligosaccharide product is effectively improved.