Along with the deepening of the research on cardiovascular disease, the elevation of blood glucose in patients with acute coronary syndrome (ACS) has aroused some attention. The patients with elevated blood glucose usually have diabetes or impaired glucose tolerance, suggesting that they may, more or less, have the potential of insulin resistance and islet beta cell insufficiency. Thus, they have poor prognosis through other mechanisms. However, there were not many reports about ACS accompanied with high blood glucose. In this paper we reviewed the incidence, causes, and adverse effects on the cardiovascular system and the prognosis of ACS accompanied by acute high glucose after our comprehensive review of related studies in recent years.