Objective To explore the effect of poly-L-lactic acid filler skin booster injection combined with high-frequency electrocautery instrument in the treatment of facial skin aging and its influence on skin texture improvement. Methods A total of 120 patients with facial skin aging admitted to Nanjing Xuanwu Yestar Medical Aesthetics Clinic from January 2023 to January 2025 were selected as the research subjects, and they were divided into the control group and the observation group by the random number table method, with 60 patients in each group. The control group was treated with simple poly-L-lactic acid filler skin booster injection, and the observation group was treated with poly-L-lactic acid filler skin booster injection combined with high-frequency electrocautery instrument. The skin texture improvement, collagen-related indicators and melanin-related indicators were compared between the two groups. Results The scores of skin texture improvement in the observation group were higher than those in the control group (P <0.05). The collagen density value of the observation group after treatment was higher than that of the control group, and the collagen density change rate, fiber arrangement score and elastic fiber content were higher than those of the control group (P <0.05). The melanin index of the observation group after treatment was lower than that of the control group, and the melanin index reduction rate, hyperpigmented area reduction rate and pigment uniformity improvement rate were higher than those of the control group (P <0.05). Conclusion Poly-L-lactic acid filler skin booster injection combined with high-frequency electrocautery instrument has a definite curative effect in the treatment of facial skin aging. It can effectively improve patients' skin texture, promote collagen regeneration, reduce melanin deposition, and comprehensively improve facial skin aging.