Objective To analyze the effect of poly-L-lactic acid treatment on skin physiological parameters in patients with hand aging. Methods A total of 40 patients undergoing hand rejuvenation treatment in the Department of Aesthetic Surgery, Xi'an International Medical Center Hospital Plastic Surgery Hospital from July 2022 to July 2023 were selected. According to the random number table method, they were divided into the control group and the study group, with 20 patients in each group. The control group was treated with autologous fat transplantation, and the study group was treated with poly-L-lactic acid. The treatment effect, skin physiological parameters, complication rate and satisfaction were compared between the two groups. Results The treatment effect of the study group was better than that of the control group (P<0.05). After treatment, the scores of texture, smoothness and moisture content in the study group were higher than those in the control group (P<0.05). The incidence of complications in the study group (15.00%) was lower than that in the control group (45.00%) (P<0.05). The treatment satisfaction rate of the study group (95.00%) was higher than that of the control group (70.00%) (P<0.05). Conclusion The application of poly-L-lactic acid in hand rejuvenation treatment can achieve good effects, effectively improve the skin condition of the hands, help to improve patient satisfaction, and has a low incidence of complications after treatment and high safety.