Abstract: To mitigate the structural impact of concentrated alkali on chitosan during its extraction process, we innovatively employed high-energy ion irradiation for the deacetylation of chitin from crayfish (Procambarus clarkii) shells. The shells were crushed and sieved through three mesh sizes (50, 100, and 200). The powder was then treated sequentially with citric acid and sodium hydroxide to remove minerals and proteins, followed by high-energy ion irradiation, decolorization with hydrogen peroxide, and finally filtration and drying to obtain chitosan samples. The effects of high-energy ion irradiation on the extraction efficiency were investigated by analyzing the particle size, apparent structure, thermal stability, protein content, and purity of the chitosan. The results indicate that the irradiated chitosan exhibited reduced particle size, a finer powder texture, a more porous structure, along with significantly enhanced purity and active site availability. The characteristic peaks of the samples closely matched those of commercial chitosan standards. A comparison between methanol and water as the processing medium reveals that the methanol-mediated treatment yielded chitosan with lower nitrogen and protein contents yet a higher overall yield, demonstrating its superiority. In conclusion, high-energy ion irradiation effectively enhances the extraction efficiency of chitosan from crayfish shells.