The invention relates to chitosan for edible insects like cicada and river shrimp and grasshopper and silkworm chrysalis, as representatives. Nowadays, the developed product in the market at home and abroad mainly includes special animal feed and edible insect food, and a quantity of insect raw material is exported as pet feed. The objective of the invention is treating the redundant insect skin filter off during edible insect treating process. The production method and application of the chitosan for edible insect realizes the commercial process and mass production. Technology is as follows: crushing and beating, separating, degreasing, decalcifying, deacetyling, decolouring, vacuum freeze drying, and meshing the edible insect skin to get the finished product. Effects are as follows: the chitosan, as the polymer material, is of unique property, safety and innocuity, well applied range, and becomes the industry raw material for making high added value byproduct in many fields like food field, medical field, cosmetic field, agriculture field, chemical industry and environmental protection field.