Objective To study the thrombolysis effect and safety of tirofiban combined with half dose reteplase in patients with ST segment elevation acute myocardial infarction .Methods 60 patients with ST segment elevation acute myocardial infarction in our hospital from January 2011 to March 2013 were selected as research object ,and they were divided into reteplase group (control group ,n=32) and tirofiban combined with reteplase group (observation group ,n=28) ,then the recanalization rate of infarct-relat-ed artery at different time and incidence of complications were compared .Results The recanalization rate of infarct-related artery of observation group at different time were all higher than those of control group (P<0 .05) ,while incidence of complications of two groups had no significant difference(P>0 .05) .Conclusion The thrombolysis effect of tirofiban combined with half dose reteplase in patients with ST segment elevation acute myocardial infarction is better ,and it does not increase the incidence of complications .