Photodynamic inactivation is a new pathogenic bacterium killing technology. It activates photosensitizers through light sources to generate reactive oxygen species that target bacterial cell membranes and DNA， causing oxidative damage and ultimately leading to bacterial death. Traditional sterilization methods are faced with many problems in the food industry， such as the emergence of drug-resistant bacteria， biofilm bacteria are difficult to kill， food nutrition and flavor loss， and the high cost to application. As a non-thermal sterilization technology， photodynamic inactivation does not cause sensory changes and nutrient loss of food， requires simple equipment and low energy consumption， does not cause bacterial resistance， and has a good killing effect on bacteria (planktonic bacteria and biofilm)， fungi， and even spores， which has attracted widespread attention in recent years. This article reviewed the limitations of traditional antibacterial methods， the principle of photodynamic inactivation， and the research progress of photodynamic inactivation in killing planktonic bacteria and biofilm bacteria are emphasized.