Abstract: Objective: To review the experience of diagnosis and surgical treatment of myasthenia gravis in 86 cases.（Methods: 86 ）patients with myasthenia gravis were operated on from January 1989 to December 2003 in our department. According Osseman clinical classification : stage in 19 cases, stage a in 27 cases, stageb in 25 cases,stage in 14 cases,stage in 1 cases.53 cases accompanied with thymoma in this group. Results: Total excision in 83 cases, partial excision in 3 cases,1 case was operated during myasthenic crisis period, anticholinesterase and glucocorticoid were used in 78 patients during preoperative and postoperative period,26 patients needed temporary mechanical ventilation,and patients with thymoma beyond stage recieved postoperative radiotherapy or chemotherapy. 2 case died of myasthenic crisis 6 months after operation. Conclusion: At present, surgical resection is the main therapeutic method for myasthenia gravis. The preferred surgical approach is through median sternotomy with resection of thymoma and perithymic fats in anterior mediastinum. anticholinesterase and glucocorticoid being used during preoperative and postoperative period remains in a key position.Some patients need temporary mechanical ventilation. Patients can be operated on during myasthenic crisis period.