SObjective To investigate the clinical application value of red-blue light combined with fractional laser technology in controlling the inflammatory phase of acne vulgaris and subsequent scar repair. Methods A total of 80 patients with moderate to severe acne vulgaris admitted to the Department of Dermatology of our hospital from September 2024 to March 2025 were enrolled. The patients were randomly divided into a control group and an observation group using a random number table method, with 40 cases in each group. The control group received conventional treatment, while the observation group received red-blue light irradiation during the inflammatory phase on the basis of conventional drug therapy, followed by fractional CO? laser treatment after inflammation was controlled. The clinical efficacy, acne lesion count, acne scar score, and adverse reactions were compared between the two groups. Results The total effective rate in the observation group was 92.50%, which was significantly higher than 75.00% in the control group (P<0.05). After 12 weeks of treatment, the number of inflammatory lesions decreased significantly in both groups, and the observation group had fewer lesions than the control group (P<0.05). After 12 weeks of treatment, the improvement in ECCA scar score in the observation group was significantly better than that in the control group (P<0.05). There was no statistically significant difference in adverse reactions between the two groups (P>0.05). Conclusion Red-blue light combined with fractional laser therapy has a significant therapeutic effect on acne, effectively controlling inflammation and improving late-stage scars.