Objective To observe the influence of insulin therapy on the short-term prognosis of patients with acute ST-elevation myocardial infarction (ASTEMI) complicated with hyperglycaemia.Methods A total of 128 patients with ASTEMI complicated with hyperglycaemia were randomized into 2 groups:treatment group and control group.There were 64 patients(50.0％ )in the treatment group and 64 patients(50.0％ ) in the control group.All of the patients were given anticoagulants,antiplatelet drugs,statins,beta-receptor blockers,nitrates and angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blocker (ARB) Moreover,the patients in the treatment group were given extra 50 U insulin ( Novolin R) in 50 ml saline by venous infusion.In the treatment group,Venous blood samples were obtained before and 7 days after treatment to determine the fasting blood glucose and hs-CRP in serum; the levels of fasting blood glucose and hs-CRP and short-term prognosis were compared between the 2 groups.Results The levels of fasting blood glucose in the treatment group were decreased significantly after treatment ( [ 5.4 ± 0.8 ] mmol/L vs [ 11.6 ± 2.3 ] mmol/L,P ＜0.01),but there was no significant change in the control group( [ 10.7 ± 2.1 ] mmol/L vs [ 11.2 ± 2.7]mmol/L,P ＞ 0.05 ).The levels of hs-CRP in both groups were decreased significantly after treatment (P ＜0.05),but it was much more obvious in the treatment group( [ 6.2 ± 1.5 ] mg/L vs [ 8.7 ± 1.8 ] mg/L,P ＜0.05).The incidence of major adverse cardiac events(MACE) during a 3 months′ follow-up in the treatment group was significantly lower than that in the control group ( 12.50％ vs 34.38％,P ＜ 0.05 ).Conclusion Insulin therapy can improve the short-term prognosis in patients with ASTEMI complicated with hyperglycaemia.