Objective To sum up the clinical manifestation of toxic diffuse goiter（Graves disease）and the causes of misdiagnosis so as to improve awareness of the Graves disease.Method Clinical data of 19cases of misdiagnosed patients with Graves disease was collected and the causes of misdiagnosis were analyzed.Results 19 cases of patients had different degrees of palpitation and shortness of breath

and there were 8cases with arrhythmia（including atrial fibrillation）

accounted for 42.1%of the misdiagnosed cases

followed by excessive appetite

thermophobia

hyperhidrosis and chronic diarrhea etc.Among the misdiagnosed cases of patients

there were 10cases who had coronary disease

hypertension and myocarditis

accounted for 52.6%of the misdiagnosed cases

followed by chronic conjunctivitis and hypokalemic periodic paralysis etc.There were 18cases in which T3and T4were increased in the thyroid function tests with a percentage of 94.7%;among the misdiagnosed cases

there were 15cases of elderly people aged 60years old or above

accounted for 78.9%.Conditions of all patients were improved after treatment by taking antithyroid drugs.Conclusion Graves disease has diversified clinical manifestations

some cases have no typical clinical manifestation but manifest as symptoms and signs of the cardiovascular system

so it is easily misdiagnosed as cardiovascular diseases.Clinicians shall have a better understanding of Graves disease and conduct thyroid function tests in time so as to improve the diagnostic rate of Graves disease.