The codon of keratinase gene kerUS from the Brevibacillus brevis US575 was optimized and expressed in Pichia pastoris GS115 to improve keratinase production. Results showed that the gene optimized was successfully expressed in Pichia pastoris. The molecular weight of recombinant keratinase was about 30 ku. The optimal reaction conditions of keratinase were pH 9.5 and 60℃. The keratinase activity was improved by 1 mmol/L Mn2+ and Ba2+. In addition,the recombinant keratinase efficiently degraded α-keratin (keratin azure) and β-keratin (feather powder). The maximum speed of the enzyme reaction,the constant Km,and the specific activity was 0.019 g/(L·min）,4.64 g/L,and 440 U/mg,respectively. It is indicated that the novel recombinant Pichia pastoris strain with keratinase production has a good application prospect.