Objective To analyze the application effect of modified myocutaneous flap combined with orbital septum fixation in eye bag plastic surgery. Methods A total of 50 patients with eye bag plastic surgery admitted to our hospital from April 2021 to April 2023 were selected as the research objects. They were divided into reference group and study group by random number table method, with 25 patients in each group. The reference group was treated with conventional muscle flap method, while the study group was treated with modified myocutaneous flap combined with orbital septum fixation. The clinical efficacy, clinical indicators, eye aesthetics, complications and treatment satisfaction were compared between the two groups. Results The total effective rate of treatment in the study group was 96.00%, which was higher than 72.00% in the reference group, the difference was statistically significant (P<0.05). The treatment time and recovery time of the study group were shorter than those of the reference group, and the differences were statistically significant (P<0.05). After treatment, the score of eye aesthetics in the study group was higher than that in the reference group, and the difference was statistically significant (P<0.05). The incidence of complications in the study group was 4.00%, which was lower than 28.00% in the reference group, and the difference was statistically significant (P<0.05). The treatment satisfaction of the study group was 100.00%, which was higher than 72.00% of the reference group, and the difference was statistically significant (P<0.05). Conclusion Modified myocutaneous flap combined with orbital septum fixation is effective in eye bag plastic surgery, which can shorten the treatment time, promote the rapid recovery of patients. Meanwhile, it can effectively improve the aesthetics of the eyes, reduce the risk of complications, and improve the treatment satisfaction of patients.