ABSTRACT. This study aimed to investigate the effect of intracoronary application of tirofiban on platelet alpha-granule membrane protein (GMP-140) and myocardial perfusion levels during emergency percutaneous coronary intervention (PCI). A total of 70 patients who accepted emergency PCI treatment were randomly divided into tirofiban and control groups. We determined GMP-140 and troponin I (cTnI) levels before and 12 h after surgery, as well as N-terminal pro-brain natriuretic peptide levels 1 and 7 days after surgery in the two groups. The results showed that GMP-140 and cTnI levels were significantly (P < 0.01) lower in the tirofiban group than in the control group 12 h after operation (17.99 ± 1.01 vs 24.56 ± 1.96 μg/L and 50.96 ± 2.20 vs 58.69 ± 2.34 ng/mL, respectively). The D-value of the N-terminal pro-brain natriuretic peptide levels between 1 and 7 days after operation was significantly higher in the tirofiban group than in the control group (894.19 ± 90.91 vs 829.50 ± 84.18 pg/mL; P < 0.01). The intracoronary application of tirofiban during emergency PCI clearly reduced the GMP-140 level, inhibited the activation function of platelets, improved myocardial perfusion, and helped recover cardiac function in patients.