Abstract: In this experiment, soybean meal was fermented by the combination of Lactic acid bacteria, Bacillus subtilis and Yeast. The test consisted of two parts, both under anaerobic fermentation temperature: (1) optimization of the fermentation time: in per 100 kg basic formula, add 55 kg of water, the fermentation time was set at 48h and 72h two levels, and each level had three replicates; (2) optimization of fermentation water: in per 100 kg basic formula, the added amount of water was set at three levels: 40kg, 55kg and 70kg, each level has three replicates, fermentation time was set at 72h. Test result showed that: (1) compared with the 48h group, the 72h group’s free amino acids Glycopeptides and (free amino acids oligopeptide)/crude protein were significantly improved (P<0.01) by 14.29% and 12.92%; pH was significantly (P<0.01) decreased by 7.26%; (2) the free amino acid protein and (free amino acids peptides)/protein of the 70kg group were significantly higher than that of the 40kg and 55kg group, the pH of the 70kg group was significantly lower than that of the 40kg and 55kg group (P<0.01), the viable probiotics counts of the 70kg group were significantly higher than that of the 40kg group (P<0.05), the peptide / protein of the 70kg group was significantly higher than that of the 40 kg group (P<0.01). Fermentation time of 72 h and add water 70 kg may be the appropriate condition for utilizing the combination of lactic acid bacteria, Bacillus subtilis and Yeast to ferment soybean meal.