A keratinase-producing strain was obtained from seven soil samples through traditional methods and identified as Streptomyces aureus K13. The K13 keratinase was proven to be a middle-temperature-alkaline enzyme with optimum temperature of 55℃ and optimum p H of 8. 5. Its molecular weight was about 46 k Da. The keratinase production was highly associated with cell growth. Its fermentation period was 64 h. Using appropriate carbon source( glucose) or nitrogen source( peptone and Na NO3) will promote keratinase production in the fermentation. By four factors and three levels orthogonal design,44. 2 U / m L keratinase was obtained under optimal fermentation conditions,which was 10. 3 times higher than the initial level.