Objective To explore the effect of modified musculocutaneous flap method combined with orbital septum fixation surgery on skin aesthetics, lower eyelid wrinkles and eyelid bag severity in patients undergoing eye bag plastic surgery. Methods A total of 96 patients undergoing eye bag plastic surgery admitted to Nantong BASILCA Medical Beauty Hospital from August 2023 to August 2024 were selected as the research subjects. According to different plastic surgery plans, they were divided into the control group and the observation group, with 48 patients in each group. The control group was treated with the traditional musculocutaneous flap method, and the observation group was treated with modified musculocutaneous flap method combined with orbital septum fixation surgery. The clinical efficacy, ocular indexes, clinical indexes, treatment satisfaction and adverse reaction rate were compared between the two groups. Results The total effective rate of clinical treatment in the observation group (97.92%) was higher than that in the control group (83.33%) (P <0.05). The skin aesthetics score in the observation group was higher than that in the control group, and the scores of lower eyelid wrinkles and eyelid bag severity were lower than those in the control group (P <0.05). The recovery time of the eye appearance and the hospitalization time in the observation group were both shorter than those in the control group, and the operation time was longer than that in the control group (P <0.05). The incidence of adverse reactions in the observation group (4.17%) was lower than that in the control group (16.67%) (P <0.05). Conclusion The application of modified musculocutaneous flap method combined with orbital septum fixation surgery in eye bag plastic surgery is beneficial to improving the eyelid bag severity, eliminating lower eyelid wrinkles, enhancing the periorbital skin aesthetics, reducing the incidence of adverse reactions, and shortening the recovery time.