Abstract: Non-obstructive coronary artery disease (NOCAD) is characterized by clinical evidence of coronary atherosclerotic heart disease without significant coronary artery stenosis on angiography and the diagnosis should exclude non ischemic causes. The prevalence of NOCAD is approximately 40% in coronary artery disease patients. Its pathogenesis mainly includes vulnerable plaque and thromboembolism, coronary microcirculation disorder and coronary artery spasm. As coronary angiography often fails to find significant vascular stenosis, the disease is easily to be ignored and the prognosis is poor. This article will review the etiology, diagnosis, treatment and prognosis of the disease.