Objective To observe the effect of poly-L-lactic acid for injection on improving facial overfilled syndrome. Methods A total of 20 patients with severe facial skin relaxation after physical filler injection in our hospital from October 2022 to January 2023 were selected as the research objects. According to different treatment methods, they were divided into control group and observation group, with 10 patients in each group. The control group was treated with micro-focusing ultrasound, and the observation group was treated with poly-L-lactic acid injection. The skin relaxation (SLGS score) and adverse reactions were compared between the two groups. Results The SLGS score of the observation group was higher than that of the control group (P0.05). Conclusion Poly-L-lactic acid is effective in improving facial overfilled syndrome, which can improve skin relaxation and has good safety.