Objective To explore the effect of combined application of ultra-pulsed carbon dioxide fractional laser and intense pulsed light on scar condition after deep second-degree burn. Methods A total of 100 patients with scar after deep second-degree burn admitted to the Department of Burn and Plastic Surgery, the First People's Hospital of Zunyi from January 2022 to October 2024 were selected, and they were divided into group A and group B according to different treatment methods, with 50 patients in each group. Group A was treated with intense pulsed light, and group B was treated with ultra-pulsed carbon dioxide fractional laser on the basis of group A. The scar condition, improvement of objective scar signs and subjective scar feelings were compared between the two groups. Results After treatment, the scores of scar thickness, softness and vascular distribution in the two groups were lower than those before treatment, and those in group B were lower than those in group A (P<0.05). The OSAS score of the two groups after treatment was lower than that before treatment, and that of group B was lower than that of group A (P<0.05). The PSAS score of the two groups after treatment was lower than that before treatment, and that of group B was lower than that of group A (P<0.05). Conclusion The application of ultra-pulsed carbon dioxide fractional laser combined with intense pulsed light in patients with scar after deep second-degree burn can more effectively reduce scar, promote the improvement of objective scar signs and patients' subjective scar feelings, which is worthy of clinical application.