Objective To investigate the effect of the combination therapy of tirofiban and reteplase on endothelial function, coagulation function and plaque inflammation in elderly patients with ST-elevation acute myocardial infarction (STEMI). Methods 100 patients with STEMI were treated with percutaneous transluminal coronary intervention (PCI) from January 2014 to June 2016 in our hospital.39 cases in the control group used conventional oral aspirin, clopidogrel and statins and other treatment.61 cases in the observation group received tirofiban and reteplase on the basis of the control group.The expression of endothelial microparticles (EMP) was detected by flow cytometry (FCM), and the ICAM-1, high sensitivity C-reactive protein (hs-CRP), tumor necrosis factor α(TNF-α) and interleukin-6 (IL-6), endothelin-1(ET-1) were measured by enzyme-linked immunosorbent assay (ELISA). The thrombin time (TT), activated partial thrombin time (APTT), prothrombin time (PT) and other indicators were measured by PUN-2048A coagulation instrument, then statistical analysis was performed. Results The postoperative levels of EMP, ICAM-1 and ET-1 of control group were (693.46±90.72), (768.58±20.46)μg/L and (31.27±8.18)ng/L, which were significantly higher than those in the observation group [(652.36±67.39), (752.37±25.0)μg/L, (28.22±5.05)ng/L], the differences were statistically significant (t=2.41, 2.67, 2.68, all P<0.05). After operation, the hs-CRP, TNF-α, IL-6 levels in the control group were (4.16±2.35)mg/L, (4.32±2.02)ng/L, (10.59±3.16)ng/mL, which were significantly higher than those in the observation group [(2.22±1.47)mg/L, (2.74±1.52)ng/L, (6.33±2.24)ng/mL], the differences were statistically significant(t=2.65, 2.67, 3.42, all P<0.05). The postoperative TT, PT, APTT in the observation group were (26.31±3.18)s, (14.34±1.67)s, (27.20±4.12)s, which were significantly longer than those in the control group [(24.03±2.84)s, (12.56±1.43)s, (24.55±3.62)s], the differences were statistically significant(t=2.15, 2.31, 2.65, all P<0.05). Conclusion Tirofiban combined with reteplase can improve endothelial function, inhibit inflammatory reaction and regulate coagulation function. Key words: Myocardial infarction; Platelet membrane glycoprotein IIb; Tirofiban hydrochloride; Reteplase