Comprehensive research data on the combination of 5-aminolevulinic acid (5-ALA) photodynamic therapy (PDT) and CO This study was a retrospective study. The subjects were 165 patients diagnosed with VSIL in the People's Hospital of Zhengzhou University. According to the patients' personal choice, they were divided into 5-ALA PDT group (n = 37), CO2 laser group (n = 78) and 5-ALA PDT combined with CO2 laser group (n = 50). The general condition, treatment times and adverse reactions of patients in each group were analyzed. All patients underwent HPV, TCT and colposcopy at 3 months and 6 months after treatment to evaluate the therapeutic effect, and biopsy was performed again if necessary. There was no statistically significant difference in the HPV negative conversion rates and lesions complete remission (CR) rates of both vulvar low-grade squamous intraepithelial lesions (VLSIL) and vulvar high-grade squamous intraepithelial lesions (VHSIL) patients among the three groups at 3 months after treatment. Regarding VLSIL, the HPV negative conversion rates for both the 5-ALA PDT group (51.7 %) and the combination group (51.9 %) were significantly higher than the CO The integration of 5-ALA PDT with CO₂ laser therapy not only reduces the overall treatment duration but also enhances treatment efficacy. Therefore, it is a promising option for treating VSIL.