Aim To study the relationship between the level of γ-glutamyltransferase(GGT) and the severity of coronary artery lesions and prognosis in patients with acute ST-segment elevation myocardial infarction(STEMI). Methods 282 cases of patients with STEMI underwent PCI were selected as the observation subjects. According to the fasting serum GGT level in the morning after admission, the patients were divided into normal group (n=197) and high-level group (n=85). The coronary artery disease, mortality and the incidence of major adverse cardiac events were analyzed and compared between the two groups. Results The Gensini score in the high level group was significantly higher than that in the normal group (P<0.05), and the GGT level was positively correlated with the Gensini score (r=0.598, P<0.05). Within one year of follow-up, 19 patients died in the high GGT group and 20 patients died in the normal group, with a total mortality rate of 13.83%. The mortality rate of 1 week, 1 month, 6 months and 1 year in the high level group was significantly higher than that in the normal group (P<0.05), the survival curve analysis showed that the 1 year mortality rate of STEMI patients in the high level group was significantly higher than that in the normal group. Cox regression analysis showed that KILLIP cardiac function grade (OR=2.9,5%CI 1.024~4.508), GGT (OR=2.8,5%CI 1.289~4.501) and age (OR=1.3,5%CI 1.032~1.095) were independent risk factors for prognosis in patients with STEMI; the incidence of major cardiovascular events (MACE) in patients with high level STEMI at 1 week, 1 month, 6 months and 1 year were significantly higher than those in normal group(P<0.05). Conclusion Serum GGT level is correlated with the degree of coronary artery disease and short-term and long-term prognosis in patients with STEMI, and high GGT level is an independent risk factor to evaluate the prognosis of STEMI patients.