To explore the application effect of platelet-rich plasma combined with ultra-pulsed CO2 fractional laser in patients with facial acne depressed scar. Methods A total of 96 patients with facial acne depressed scar admitted to the Department of Plastic and Burn Surgery, Guizhou Provincial People's Hospital from January 2022 to January 2023 were randomly divided into group A and group B, with 48 patients in each group. Group A was treated with ultra-pulsed CO2 fractional laser, and group B was treated with ultra-pulsed CO2 fractional laser combined with platelet-rich plasma. The clinical efficacy, recovery time and adverse reactions were compared between the two groups. Results The total effective rate of treatment in group B was 87.50%, which was higher than 70.83% in group A , and the difference was statistically significant (P <0.05). The recovery time of group B was shorter than that of group A , and the difference was statistically significant (P <0.05). The incidence of adverse reactions in group B was 2.08%, which was lower than 16.67% in group A, and the difference was statistically significant (P <0.05). Conclusion Platelet-rich plasma combined with ultra-pulsed CO2 fractional laser is effective in the treatment of facial acne depressed scars, which can effectively improve the clinical symptoms of patients, shorten the recovery time, and have less risk of adverse reactions and higher treatment safety.