The invention belongs to microbial fermentation and particularly relates to a method for preparing an aspergillus oryzae lactase fermentation starter by solid pot fermentation. The method comprises the technical steps such as preparation of a spore suspension, solid pot fermentation and starter tray cultivation. The method solves the technical problems of long fermentation period, high microbiological contamination and the like of the prior art, and has the advantages of short fermentation period, low microbiological contamination, high production efficiency and the like.