We report the thoracoscopic resection of thymus and pericardial fat tissue in a patient who was in the setting of late severe myasthenia gravis[Osserman`s Group II-C-2 and previous tracheostomy state. The patient was 33-year-old female. She had been supported with mechanical ventilator for 88 days and suffered from recurrent pneumonia. Our first aim was to weaning her from mechanical ventilator. Traditional methods such as median sternotomy or transcervial thymectomy or transsternal sternotomy were difficult because of the anticipating complications of mediastinitis or morbidity, especially chest pain, following thoracotomy. We could wean her from the mechanical ventilator at postoperative 9 days. So, we concluded that video-assisted thoracoscopic thymectomy is a useful alternative tool in this case.