The Na-Chlorophyllin photodynamic sterilization of Staphylococcus aureus in liquid food was investigated in this study. Results found Na-Chlorophyllin showed a photodynamic inactivation against Staphylococcus aureus in several liquid foods, and the optimum concentration of Na-Chlorophyllin was 10-5 mol/L for photodynamic inactivation of Staphylococcus aureus. Staphylococcus aureus reduced about 4.5 log in 10 min. The inactivation of Staphylococcus aureus in liquid food was significantly increased with the extension of illumination, especially in the initial 10 min. Moreover, food packing materials with good light transmission had no effect on photodynamic inactivation of Staphylococcus aureus, but the pH of liquid food can affect the photodynamic inactivation of Staphylococcus aureus. In addition, photodynamic inactivation of Staphylococcus aureus in clear liquid foods was greater as compared with cloudy liquid food.