Objective To explore the effect of Yiqi Qianzheng decoction on palpebral fissure height and ptosis severity in patients with ptosis caused by myasthenia gravis. Methods A total of 80 patients with ptosis in ocular myasthenia gravis admitted to Suzhou Hospital of Traditional Chinese Medicine Affiliated to Nanjing University of Chinese Medicine from January 2024 to January 2025 were divided into the reference group and the study group by the random number table method, with 40 patients in each group. The reference group received conventional Western medicine treatment, and the study group was additionally treated with Yiqi Qianzheng decoction on the basis of the reference group. The palpebral fissure height, ptosis severity, adverse reaction rate, treatment effect, recurrence rate and quality of life were compared between the two groups. Results After 12 weeks of treatment and at 12 months of follow-up, the palpebral fissure height of the study group was higher than that of the reference group, and the ptosis score was lower than that of the reference group (P <0.05). There was no statistically significant difference in the incidence of adverse reactions between the two groups (P >0.05). The total effective rate of the study group (90.00%) was higher than that of the reference group (72.50%) (P <0.05). The recurrence rate of the study group (7.50%) was lower than that of the reference group (25.00%) (P <0.05). At 12 months of follow-up, all quality of life scores in the study group were higher than those in the reference group (P <0.05). Conclusion Yiqi Qianzheng decoction achieves favorable efficacy in patients with ptosis caused by myasthenia gravis. It can effectively improve palpebral fissure height, alleviate ptosis severity, and provide stable therapeutic effect, without increasing the incidence of adverse reactions. Furthermore, it has a low recurrence rate and good safety, which helps to improve patients’ quality of life.