Objective:To discuss the perioperative symptom change rule of patients with myasthenia gravis(MG), and to provide a theoretical basis for preventing and reducing the surgical risk of patients with MG.Methods:The clinical data of 104 patients who underwent thymectomy in the Department of Thoracic Surgery of the Second Affiliated Hospital of Zhengzhou University from 2015 to 2019 were retrospectively analyzed. According to the degree of the impact of MG symptoms on the body's physiology and life, the "MG dynamic classification standard" was formulated, which was divided into type 0-type Ⅳ according to the severity of MG symptoms. The symptoms of each patient of "admission", "preoperative" and "postoperative" are classified according to the "dynamic classification criteria", and the number of "admission", "preoperative" and "postoperative" were counted respectively. Based on the statistical analysis of each patient's type changes, the perioperative symptom changes of myasthenia gravis patients were summarized.Results:1. "Admission" classification: 12 cases of type 0, 42 cases of type Ⅰ, 32 cases of type Ⅱ, 12 cases of type Ⅲ, 5 cases of type Ⅳa, and 1 case of type Ⅳb. 2. "Preoperative" classification: 44 cases of type 0, 34 cases of type Ⅰ, 14 cases of type Ⅱ, 12 cases of type Ⅲ; 68 cases of preoperative symptom reduction (65.4%, 68/104), 36 cases of preoperative symptom stable (34.6%, 36/104). Asymptomatic aggravation. 3. "Postoperative" classification: 49 cases of type 0, 21 cases of type Ⅰ, 11 cases of type Ⅱ, 10 cases of type Ⅲ, 9 cases of type Ⅳa, 4 cases of type Ⅳb; 33 cases (31.7%, 33/104) had postoperative symptoms aggravated. Among the patients with worsening symptoms after surgery, 5 cases (15.2%, 5/33) worsened on the first day after surgery, 9 cases (27.2%, 9/33) worsened on the second day after surgery, and 13 cases (39.4%, 13/33) worsened on the third day after surgery. There were 4 cases (12.1%, 4/33) worsened on the 4th day, and 2 cases (6.1%, 2/33) worsened on the 5th day after surgery.Conclusion:MG patients had different conditions at admission. After individualized perioperative treatment, more than half of the patients' symptoms alleviated to varying degrees. After the operation, the symptoms of MG will be temporarily aggravated due to the effects of surgery and anesthesia, and the aggravation period is mostly on 1-3 days. Reasonable selection of low-risk MG patients for surgery, avoiding the superposition of other influencing factors in the postoperative exacerbation period, is expected to reduce the occurrence of postoperative crises in MG patients.