Abstract Objective To study the influencing factors of myasthenic crisis in non-thymoma myasthenia gravis (MG) patients during perioperative period. Methods We retrospectively analyzed a total of 387 non-thymoma MG patients who underwent extended thymoma resection in the Department of Thoracic Surgery of Beijing Hospital from February 2011 to December 2021, recorded ASA score, Osserman classification, preoperative course, pyridostigmine dosage, operation method, operation time, and intraoperative blood loss, then analyzed the factors associated with postoperative myasthenic crisis by univariate and multivariate logistic regression. Results Osserman classification IIB + III + IV (P