Abstract: Response surface methodology ( RSM) was used for optimizing the technological conditions of bacterial sterilization on fresh milk treated by pulsed light. In this paper, flash frequency, flash distance, flash energy and thickness of liquid were selected as influencing factors and sterilization rate was selected as response value.The results indicated that 29Hz flash frequency, 12.8cm flash distance, 300J flash energy and 2mm thickness of liquid sample of pulsed light had the best sterilization efficacy. Under this condition, the sterilization rate could reach 99.996%, flash have a maximum impact on sterilization bacterium effect of fresh milk.