OBJECTIVE To study preparation and characterization of chitosan from Catharsius Molossus processing discards and explore the feasibility of utilization of insects residue. METHODS Preparation technique of chitosan was studied by orthogonal design,and properties were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), etc. RESULTS Preparation techniques were as follows: demineralizing: soaked for 30 min at 80 degrees C with 1.3 mol/L HCl, then kept for 12 h under room temperature. Deproteinization and delipidation: treated for 6 h at 90 degrees C with 4 mol/L NaOH. Decolorizing: soaked at room temperature with 3% KM-nO4, then treated with 2% oxalic acid at 70 degrees C. Deacetylating:treated for 5 h at 110 degrees C with 14 mol/L NaOH. CONCLUSION The technique is stable and feasible. The result also preliminarily showes that chitosan from Catharsius Molossus is better than shrimp's. It will be widely applied in biomedical and other industrial areas with such exciting properties.