Objective To analyze the improvement effect of CO2 lattice laser and PRP external treatment on skin condition of patients with acne atrophic scar. Methods 120 patients with acne atrophic scars admitted to our hospital from June 2020 to June 2023 were selected as the research objects. They were divided into reference group and observation group by random number table method, with 60 cases in each group. All patients were treated with CO2 laser. The reference group was treated with fusidic acid cream, and the observation group was treated with PRP. The improvement of acne scars, scar scores, adverse reactions and satisfaction were compared between the two groups. Results The total effective rate of the observation group was 98.33%, which was higher than 81.67% in the reference group (P <0.05). The scar score of the observation group was lower than that of the reference group (P <0.05). The incidence of adverse reactions in the observation group was lower than that in the reference group (P <0.05). The satisfaction of the observation group was higher than that of the reference group (P <0.05). Conclusion The application of CO2 lattice laser combined with PRP external treatment in patients with atrophic acne scars can achieve good results, which can further reduce the scar symptoms of patients and improve their skin status, with low risk of adverse reactions and high patient satisfaction.