The invention relates to a novel biomimetic affinity purification material and its application in the purification of chitosanase, which belongs to the field of industrial biotechnology. The affinity ligand for the biomimetic affinity material is chitodisaccharides, the connecting arm is cyanuric chloride, and the base medium is epoxy-activated Sepharose™ 6B. The desorption constant (Kd) and the theoretical maximum adsorption capacity (Qmax) of the biomimetic affinity material are 24.2 μg/mL and 24.1 mg/g, respectively. Using the above biomimetic affinity material, a chitosanase biomimetic affinity purification method is established, which can produce high-purity chitosanase with high efficiency and low cost, and has good industrial application potential.