In this study, we optimized the fermentation parameters of poly-γ-glutamic acid produced by Bacillus subtilis, a strain selected through a lab screen. A single factor experiment and PB experiment were first carried out, and then the optimal composition of the medium and optimum culture conditions were obtained by optimizing the fermentation process with Box-Behnken. The yield of γ-PGA increased from 6.03 g·L^-1 to 10.98 g·L^-1 at the shaker level. We further explored the feeding process to determine the best time and feeding materials. Finally, a 5 L fermentor was used to increase the production, and the highest yield of γ-PGA reached to 31.18 g·L^-1.