Objective To investigate the efficacy and safety of fractional erbium laser combined with gold microneedle and collagen dressing in the treatment of acne depressed scar. Methods A total of 80 patients with acne depressed scar admitted to Changshu Times Medical Beauty Clinic from February 2021 to April 2024 were selected as the research subjects. According to the random number table method, they were divided into the control group and the observation group, with 40 patients in each group. The control group received fractional erbium laser combined with gold microneedle treatment, and the observation group received fractional erbium laser combined with gold microneedle and collagen dressing. The acne scar condition, recovery status, serum inflammatory factor levels, clinical efficacy and adverse reactions were compared between the two groups. Results The ECCA score of the observation group after treatment was lower than that of the control group (P <0.05). The descrustation time and lost work time in the observation group were shorter than those in the control group (P <0.05). The levels of IL-10, IL-7 and TNF-α in the observation group after treatment were lower than those in the control group (P <0.05). The total effective rate of treatment in the observation group was 95.00%, which was higher than 77.50% in the control group (P <0.05). The incidence of adverse reactions in the observation group was 5.00%, which was lower than 22.50% in the control group (P <0.05). Conclusion For patients with acne depressed scar, the application of fractional erbium laser combined with gold microneedle and collagen dressing can improve the therapeutic effect, alleviate scar conditions, shorten recovery time, relieve systemic inflammatory response, and reduce the incidence of adverse reactions, with high safety.