Abstract: Ultra high pressure processing(UHPP) to Bacillus subtilis was investigated, and all experiments were designed and optimized with Box-Behnken concept of response surface methodology(RSM). Results show that the pressure, temperature and dwell time are the significant factors for ultra high pressure sterilization to Bacillus subtilis, and the significant order is as follows: pressure＞temperature＞dwell time. The regression equation (model) for UHPP to Bacillus subtilis was established, and also verified with the check experiments. The optimized processing parameters of 10 groups were obtained, and the scales of variable factors to sterilize Bacillus subtilis of 10⁶ cfu/mL are as follows: pressure 343.79～475.75 MPa, temperature 27.47～57.44℃ and dwell time 14.14～19.72 min.