Clinical studies have shown a dose link between subclinical thyroid dysfunction and car-diovaseular disease. Subclinical hypothyroidism is associated with many cardiometabolic risk factors including dyslipidemia, hypercoagulabale state and decreased fibrinolytic activity ,and therefore contributes to increased risk for atherosclerosis,coronary artery disease and cardiovascular mortality. On the other hand, it has been reported that subclinical hyperthyroidism is associated with atrial fibrillation. However,the association of sub-clinical hyperthyroidism with cardiovascular mortality remains unclear. At present, there is no definite conclu-sion that the treatment of subclinical thyroid dysfunction can bring cardiovascular benefit.