Salmon is popular among consumers because of its rich nutrition and tender taste, but it is easy to be contaminated by microorganisms during processing and storage, resulting in nutrient loss and tissue structure destruction. In this study, curcumin was used as photosensitizer to preserve salmon by Photodynamic technology （PDT）. The bacteriostatic efficiency of curcumin-mediated photodynamics was investigated by detecting the proliferation of microorganisms in salmon treated with PDT, and the mechanism of PDT to guarantee the quality of salmon was preliminatively explored from the perspective of color difference, endogenous enzyme activity, tissue slices and water migration. The results showed that 150 μmol/L curcumin combined with light treatment for 1 h could effectively kill 1.6 log₁₀CFU/g microorganisms in salmon. In addition, curcumin-mediated PDT significantly inhibited the activity of ATPase and lipase in salmon, delayed the degradation of free amino acids and free fatty acids, thus guaranteeing the structural integrity and moisture content of salmon, and extended its shelf life by 2 d. This study can provide data and theoretical support for the photodynamic technology to guarantee the quality of salmon, and promote its practical application in the field of food preservation.