Abstract: A compound microbial consortium H2 antagonistic to multiple pathogenic fungi of potato is provided, along with an application and a preparation method thereof, all pertaining to the field of biological control. The compound microbial consortium H2 is prepared by mixing Bacillus subtilis, Bacillus atrophaeus, and Bacillus wiedmannii, and has a relatively strong inhibitory effect on Alternaria solani and Alternaria alternata, which are pathogenic fungi of potato early blight; Fusarium solani, Fusarium oxysporum, and Fusarium equiseti, which are pathogenic fungi of wilt/dry rot; and Didymella glomerata, which is a pathogenic fungus of leaf/stem spot, with all the fungal inhibition 10 rates higher than 46%, and with the Alternaria alternata inhibition rate being the highest at 75.97%. H2 is also relatively good at promoting plant growth. Thus, H2 contains high-quality strains for comprehensive prevention and control of potato soil-borne diseases and has promising prospects in field application.