The present disclosure relates to a Bacillus amyloliquefaciens CJ14-6 strain isolated from traditional meju, a preparation method for soybean koji using the same, and a soybean koji prepared by the preparation method. The preparation method for soybean koji includes: soaking soybeans in water or adding waster to soybeans and steaming the soaked soybeans; and inoculating a Bacillus amyloliquefaciens CJ14-6 strain into the steamed soybeans, fermenting the steamed soybeans, and drying the fermented soybeans to prepare a soybean koji.