Objective To explore the effect of fractional laser combined with microablation therapy on skin barrier indicators in patients with acne scar. Methods A total of 100 patients with acne scar admitted to our hospital from June 2023 to June 2025 were selected. According to the random number table method, they were divided into the control group and the observation group, with 50 patients in each group. The control group was treated with fractional laser, and the observation group was treated with fractional laser combined with microablation therapy. The skin barrier indicators, scar severity, adverse reaction rate and scar area were compared between the two groups. Results After treatment, the TEWL, SCH and pH value in the observation group were better than those in the control group (P<0.05). The scores of VSS and ECCA in the observation group were lower than those in the control group (P<0.05). There was no statistically significant difference in the incidence of adverse reactions between the two groups (P>0.05). The scar area in the observation group was smaller than that in the control group (P<0.05). Conclusion The application of fractional laser combined with microablation therapy in patients with acne scar can effectively improve skin barrier indicators, reduce scar severity, help to reduce scar area and improve skin appearance, without increasing the risk of adverse reactions, which is worthy of clinical application.