Objective To explore the effect of multi-plane injection of hyaluronic acid combined with collagen therapy on tear trough aging in patients with tear trough deformity. Methods A total of 120 patients with tear trough deformity admitted to Department of Cosmetic Surgery, Weiyan Shidai (Beijing) Medical Aesthetic Clinic from August 2024 to August 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 received multi-plane injection of hyaluronic acid, and the observation group received additional collagen therapy on the basis of the control group. The improvement of Barton grade, tear trough aging and complication rate were compared between the two groups. Results The improvement rate of Barton grade in the observation group (100.00%) was higher than that in the control group (90.00%) (P<0.05). The tear trough depth, pigmentation degree, fat pad ptosis degree, skin fold degree scores and total TTRS score in the observation group after treatment were better than those in the control group (P<0.05). The incidence of complications in the observation group (8.33%) was lower than that in the control group (25.00%) (P<0.05). Conclusion Multi-plane combined injection of hyaluronic acid and collagen in the treatment of tear trough deformity can more effectively improve tear trough depression, reduce aging appearance and reduce the risk of complications.