Objective To analyze the effect of poly-L-lactic acid in the treatment of patients with facial skin photoaging. Methods A total of 82 patients with facial skin photoaging who received treatment in Hangzhou Aidali Medical Beauty Hospital from January 2024 to June 2025 were selected, and they were divided into the control group and the observation group by the random number table method, with 41 patients in each group. The control group was treated with sodium hyaluronate gel, and the observation group was treated with poly-L-lactic acid. The skin analysis system (VISIA) scores, treatment effect and complication rate were compared between the two groups. Results The scores of all indicators of VISIA in the observation group after treatment were higher than those in the control group (P<0.05). The total effective rate of the observation group (97.56%) was higher than that of the control group (82.93%) (P<0.05). The incidence of complications in the observation group (4.88%) was lower than that in the control group (19.51%) (P<0.05). Conclusion Poly-L-lactic acid has a deffnite effect in the treatment of facial skin photoaging, which can effectively improve the symptoms of skin aging in patients, and enhance the treatment effect. The incidence of complications after treatment is low and the safety is good.