Objective：To explore the incidence of major adverse cardiovascular events（MACE）in acute myocardial infarction（AMI）patients with type 2 diabetes mellitus（T2DM）after primary percutaneous coronary intervention（PCI）. Methods：A total of 230 AMI patients who received primary PCI were included in our hospital from September，2011 to June，2015. The patients were divided into two groups：the AMI+T2DM group（n=103）and the AMI group（n=127）. The clinical characteristics，coronary angiographic features，PCI outcomes，and incidence of major adverse cardiovascular events（MACE）including cardiac death，heart failure，target vessel revascularization and thrombosis within the stent at 30 days and 3 years were compared. Results：There was no difference in acute successful rate of intervention between the two groups. At 30 days after PCI，the incidence of heart failure was higher in the AMI+T2DM group than that in the AMI group（10.67% vs. 3.14%，P=0.03）. However，no significant differences in rate of thrombosis within stent and target vessel revascularization（TVR）were observed（1.94% vs. 0.79%，4.85% vs. 3.15%，respectively，both P > 0.05）. During 3-year follow up period，the incidences of cardiac death，TVR and heart failure were significantly higher in AMI patients with T2DM than without T2DM patients（8.93% vs. 2.36%，P=0.032；6.79% vs. 0.79%，P=0.024；14.56% vs. 4.72%，P=0.012，respectively）. Conclusion：Compared to AMI patients without T2DM，the incidence of TVR was significantly higher during long-term follow up and the incidence of heart failure was significantly higher during both short- and long-term follow up in AMI patients with T2DM.