The invention discloses a bean yoghourt fermenting agent with 
processing suitability as well as a preparation method and application thereof, and belongs to the field of bioengineering. The preparation method of the bean yoghourt fermenting agent with the 
processing suitability comprises the following steps: an exogenous microbial 
population is added into reconstituted milk, and the exogenous microbial 
population, the reconstituted milk and 
Kefir grains are mixed and fermented; after multi-generation 
domestication, a 
Kefir fermenting agent is reformed, so that the microbial 
population structure of the reformed 
Kefir fermenting agent is changed, and the reformed Kefir fermenting agent is used for fermenting bean milk so as to produce bean yoghourt; soybean isoflavone can be biologically converted, so that concentration of 
genistein and 
daidzein in the bean yoghourt is improved; the reformed Kefir grains are adopted to prepare the fermenting agent so as to ferment the beam milk, so that the Kefir bean yoghourt is smooth in taste and rich in 
nutrition, absorption and utilization of vegetable 
protein for a 
human body can be improved, and probiotics in the bean yoghourt is increased; the soybean isoflavone can be biologically converted, so that the concentration of the 
genistein and the 
daidzein in the bean yoghourt is improved, and the 
bioavailability of the soybean isoflavone is improved.