Provide in the present invention is a method for preparing fermentation broth extracts having milk-clotting activity, comprising the steps of: obtaining the fermentation broth by culturing Paenibacillus CGMCC No. 8333 using a wheat bran broth, and obtaining the extracts by taking the supernatant after centrifuging the resulting fermentation broth. Using these fermentation broth extracts, liquid milk can curdle in a short time, and non-specific hydrolysis of casein is low.