The invention discloses a keratinase mutant subjected to thermal stability modification and belongs to the technical field of industrial biotechnologies. Based on a keratinase three-dimensional structure model, aiming at eight key amino acid residue sites in a zymoprotein Loop region of keratinase, the thermal stability mutant recombinant bacteria are constructed by adopting one-step inverse PCR (Polymerase Chain Reaction). The thermal stability research results show that the thermal stability of the mutant N218S keratinase at 60 DEG C is improved by 3 times or more. The keratinase is used forperforming feather-degrading study. The feather surface is observed to be split and roughened within 48 hours after keratinase treatment, the feather-degrading rate reaches 25%, and the total contentof amino acids in the feather degradation liquid is increased by 1.82mg/mL. The study lays a foundation for degrading the feather to prepare high-quality feed and degrading hard keratin wastes.