Diabetes is a chronic metabolic disease with elevated blood sugar as the main cause. Long-term poor blood sugar control will produce a variety of complications such as heart, brain, kidney, nerve and fundus that endanger patients’ lives. The harm of diabetes to the heart mainly includes the following: First, diabetic macroangiopathy leads to coronary atherosclerosis, so diabetic patients are prone to complications of coronary heart disease, and even angina pectoris, myocardial infarction, etc. Compared with non-diabetic patients, coronary heart disease in diabetic patients has a younger age of onset and more diffuse lesions, mostly manifesting as multiple coronary vascular involvement, with more thrombosis and more severe disease. Diabetic microangiopathy, diabetes can cause microangiopathy in the heart, prone to punctate necrosis of the myocardium, affecting the contractile function of the heart. Third, diabetic neuropathy, diabetic vegetative neuropathy can lead to poor heart rate variability in diabetic patients, which can easily lead to cardiac arrest. Diabetic neuropathy can also make cardiac symptoms atypical, such as painless myocardial infarction.