Abstract: The fermentation media and conditions for the strain of Bacillus subtilis BZJN1 had been optimized. It showed that the composition of the optimized medium was as followings： W23Corn starch 25.0 g/L, fish meal 25.0 g/L, peptone 15.0 g/L, corn steep liquor 5.0 g/L, CaCO₃ 1.0 g/L, MgSO₄ 0.3 g/L and KH₂PO₄ 0.1 g/L. The optimized fermentation condition was as following：Starting pH 7.0, temperature 30 ℃, inoculum ratio 4%, and stirring speed 220 r/min. The spore counts of the fermentation culture might reach 9.68×10⁹ CFU/mL under the optimized condition with tthe optimized medium, which was about 2 times higher than that in the primary medium and fermentation condition.

Key words: Bacillus subtilis, fermentation medium, condition, optimization