BACKGROUND: Moderate-to-severe acne vulgaris, which is a chronic inflammatory skin disease, seriously impacts millions of people. However, traditional therapies may cause severe adverse reactions that are unacceptable to many patients, thus limiting the further application of these therapies. Novel therapeutic approaches to effectively treat moderate-to-severe acne vulgaris with minimal adverse reactions are urgently needed. In this retrospective study, we investigated the efficacy and adverse reactions of photodynamic therapy (PDT) using 560-1200 nm followed by 420-1200 nm broadband light (BBL). METHODS: Twenty-four patients with moderate-to-severe acne vulgaris were included in the study and all patients expressed a strong desire for beauty. After aminolevulinic acid (ALA) gel applied, the entire face was sequentially irradiated by using BBL with a 560 nm cut-off filter (560-1200 nm), followed by BBL with a 420 nm cut-off filter (420-1200 nm). The clinical efficacy was evaluated by the proportion of patients achieving cured response and excellent response (effective rate), based on the percentage of lesions reduction (treatment rate). The fluorescent images and photographs of acne vulgaris were recorded. Pain and other common local adverse reactions during the treatment were also recorded and evaluated. RESULTS: In patients with moderate acne, the mean treatment rates were 57.74 ± 16.40 (%) and 87.40 ± 8.521 (%) at the 6th week and 12th week of treatment, respectively. In patients with severe acne, the mean treatment rates were 60.95 ± 12.06 (%) and 85.04 ± 9.115 (%) at the 6th week and 12th week of treatment, respectively. At the 6th and 12th weeks of treatment, the effective rates of patients were 20.00 % and 93.33 % in patients with moderate acne, and 0.000 % and 88.89 % in patients with severe acne, respectively. Pain scores were significantly higher in patients with severe acne compared to patients with moderate acne when receiving 560-1200 nm BBL-PDT. Additionally, patients when receiving 420-1200 nm BBL-PDT exhibited significantly higher pain scores than those when receiving 560-1200 nm BBL-PDT. The degree of erythema was more severe in patients with severe acne than in those with moderate acne. The pigmentation was observed in one patient with moderate acne and one patient with severe acne. CONCLUSION: The 560-1200 nm and 420-1200 nm BBL-PDT therapy can effectively treat moderate-to-severe acne vulgaris with tolerable adverse reactions, providing a new option for patients with higher esthetic requirements.