Some patients with typical exertional angina, positive ECG exercise test, and normal coronary angiogram have a disease called syndrome X. The main feature of syndrome X is coronary microvascular spasm, coronary microvascular angina, and these patients are suffering from myocardial ischemia due to reduced dilatation reserve function of small coronary arteries and coronary artery constriction. Their lesions are located in the small precoronary arteries that cannot be visualized by current coronary angiography techniques. When the small precoronary arteries have a lamellar distribution of abnormal vasoconstriction, it causes distal localized myocardial ischemia and produces chest pain. Psychological and psychiatric factors are important influencing factors. Coronary microvascular angina pectoris (syndrome X) is most often seen in young or middle-aged female patients, often without coronary risk factors (e.g., smoking, hypertension, hyperlipidemia, diabetes, obesity, etc.). There is no specific treatment for this disease. Pharmacological treatment can partially relieve symptoms with nifedipine or thiodiazepine. Nitrates can improve the symptoms in some patients, but cannot improve exercise tolerance. The prognosis of this disease in the near and long term is good.