Periodontitis is a chronic infectious disease caused by periodontal pathogens, characterized by pathological features such as gingival bleeding, alveolar bone resorption, tooth loosening, displacement and loss. Non-surgical periodontal treatment refers to methods of eliminating pathogenic bacteria and controlling periodontal inflammation through non-surgical approaches. Photodynamic therapy (PDT) is one of the commonly used methods in non-surgical periodontal treatment, with advantages of high sensitivity, few side effects, minimal invasiveness, low tendency to induce drug resistance, and a broad antibacterial spectrum. Combining it with periodontal treatment methods can effectively overcome the limitations of traditional treatment methods. Based on this, this paper systematically reviews the mechanism of PDT and its application potential in non-surgical periodontal treatment.