The invention relates to the field of bioengineering, in particular to a preparation method and an application of a 
microbial agent composition for enhancing secondary 
fermentation of a bean paste. The 
microbial agent composition consists of a 
saccharomycetes agent, an 
aspergillus oryzae agent and a pleospora agent; and the three microbial agents are prepared, and then the prepared microbial agents are mixed with the secondary-fermented bean paste, so as to promote the secondary 
fermentation of the bean paste. The whole process of the preparation method of the 
microbial agent composition provided by the invention is applicable to continuous industrial production; by-products (chili and radix platycodonis), from the production of Pixian bean paste, are comprehensively utilized; a 
production cycle can be shortened by 6 months, the content of amino 
nitrogen can be improved by 20% and the content of volatile 
aroma-producing components can be improved by more than 3 times (the contents of total ester, 
total acid and total 
aldehyde); by inoculating 
aflatoxin B1 with the 
saccharomycetes agent at a production peak (after being fermented for 30-60 days), an ester producing and 
aroma generating process can be enhanced, the 
metabolism of 
aspergillus flavus and partial 
aspergillus parasiticus can be competitively inhibited and the content of the 
aflatoxin B1 can be reduced, and the content of the 
aflatoxin B1 is lower than 0.5ppm, so that 
food safety is enhanced.