Objective: To investigate the clinical efficacy of multi-plane injection of hyaluronic acid combined with collagen in the treatment of tear trough deformity.Methods: A total of 120 patients with tear trough deformity admitted to our clinic from August 2024 to August 2025 were selected and divided into two groups using a random number table method. The control group was treated with multi-plane injection of hyaluronic acid alone, while the observation group received collagen therapy on the basis of the control group"s treatment. The improvement rate of Barton classification, changes in the degree of tear trough deformity, postoperative complication rate, and postoperative satisfaction were compared between the two groups.Results: The improvement rate of Barton classification in the observation group was 100%, which was significantly higher than 90.00% in the control group (P<0.05). Before treatment, there were no significant differences in tear trough depth, pigmentation degree, fat pad ptosis degree, skin fold degree, and total Tear Trough Rating Scale (TTRS) score between the two groups (P>0.05). After treatment, the improvement of all the above indicators in the observation group was significantly better than that in the control group (P<0.05). The postoperative complication rate in the observation group was 8.33%, which was significantly lower than 25% in the control group (P<0.05). The postoperative satisfaction rate in the observation group was 95%, which