About 15% to 20% of patients with myasthenia gravis (MG) develop a myasthenic crisis, which involves the respiratory muscles, leading to weakness in coughing, difficulty breathing, and an inability to maintain normal ventilation. Early assessment of respiratory muscle function in MG patients helps provide a basis for judging the risk of developing a myasthenic crisis. The diaphragm is the main respiratory muscle, and examining diaphragmatic function is beneficial for early evaluation of respiratory function in MG patients. However, previous literature on diaphragmatic function research lacks effective integration. This article will summarize and review factors affecting MG antibodies, clinical classifications, mechanisms of diaphragmatic dysfunction occurrence, manifestations, examinations, diagnostic methods, etc., providing references for in-depth research and clinical applications of respiratory function in MG patients.