To explore the application effect of ultra-pulsed CO2 fractional laser in the treatment of facial depressed scars. Methods A total of 88 patients with facial depressed scar admitted to our hospital from January 2022 to January 2023 were selected as the research objects and divided into control group and observation group by random number table method, with 44 patients in each group. The control group was treated with traditional fractional laser, and the observation group was treated with ultra-pulsed CO2 fractional laser. The clinical efficacy, ECCA score and adverse reactions were compared between the two groups. Results The total effective rate of treatment in the observation group was 93.18%, which was higher than 77.27% in the control group (P <0.05). The ECCA scores of the observation group after 1 and 2 treatments were lower than those of the control group (P <0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P >0.05). Conclusion The effect of ultra-pulsed CO2 fractional laser in the treatment of facial depressed scar is ideal, which is beneficial to improve the overall treatment effect, improve the skin condition of patients, and reduce the serious complications of patients, with higher safety.