Abstract: Objective: To evaluate the efficacy of tirofiban by intracoronary administration on TIMI flow in acute coronary syndrome (ACS) with no-reflow phenomenon after percutaneous coronary intervention (PCI).Methods: Forty-eight ACS patients with no-reflow phenomenon after PCI were randomized to tirofiban group (intracoronary verapamil and tirofiban,10 μg/kg,n=25) and verapamil group (intracoronary verapamil,200 μg,n=23).The TIMI flow at 30 min post-medication,corrected TIMI frame count (CTFC),left ventricular ejection fraction after PCI for 7 days,hemorrhage complication and incidence of major adverse cardiovascular events (MACE) within 30 days after PCI were observed in both groups.Results: The TIMI 3 ratio in tirofiban group (64.0%) was markedly higher than that in verapamil group (34.8%) (P<0.05);CTFC showed that the coronary blood flow in tirofiban group was faster than that in verapamil group (P<0.01);the left ventricular ejection fraction after PCI for 7 days was higher in tirofiban group than in verapamil group (P<0.01);the difference between the hemorrhage complication and the incidence of MACE within 30 days after PCI was not significant (P>0.05).Conclusions: Intracoronary administration of tirofiban is effective and safe for ACS patients with noreflow phenomenon after PCI.