Myasthenia gravis is a thymus-related disease caused by autoimmune dysfunction, 70% of which are associated with thymic hyperplasia and 20% with thymoma. The efficiency of thymectomy treatment is 60% to 90%, of which about 40% of patients can have basic remission of myasthenia gravis symptoms, and a significant proportion of patients have stable symptoms that no longer progress, which may be related to the correction of peripheral blood T-cell disorders in MG patients. Therefore, if there is no contraindication to surgery, thymectomy should be performed in patients with onset before the age of 60, systemic type and oculomotor type with ineffective drug treatment, regardless of whether the thymus gland is hyperplastic or not. Firstly, it is related to the pathological type of thymus. Patients with simple thymic hyperplasia have the best results in thymectomy, followed by benign thymoma, thymic atrophy and malignant thymoma; secondly, it is related to the patient’s age and disease duration, young patients have the best results in early new thymectomy, while those with onset after 60 years of age and disease duration of more than 5 years have poorer results. It is important to note that the surgical stress of thymectomy may lead to a transient worsening of postoperative symptoms, myasthenia gravis crisis, and the need for higher doses of postoperative medications and possibly even a ventilator to survive the surgical stress. The effects of surgery often take months to years to slowly appear. When is the best time to operate? Once myasthenia gravis is diagnosed, surgery should be performed as soon as possible, provided that the indications for surgery are met. Surgery should be performed when the symptoms are mildest, the medication dose is minimal, and there are no recent upper respiratory tract infections, fever, or emotional stability. Which patients are not suitable for thymectomy? Patients who present with myasthenia gravis should not receive immediate surgical treatment, but should be treated with medication to control symptoms before surgery, which can reduce the occurrence of postoperative crisis. In addition, if there are chronic diseases such as hypertension and diabetes, effective treatment should be given and surgery should be performed when the condition is stable and well controlled. For those with poor general condition and malnutrition, surgery should be performed after improving the physical condition; for those with lung infection, surgery should be performed after controlling the infection. For those who are >60 years old, with a disease duration >5 years, and with good results of drug treatment, surgery should be carefully selected.