OBJECTIVE： To explore the effect of Buchang naoxintong capsule on the myocardial perfusion and platelet activation function in patients with acute myocardial infarction （AMI） after PCI. METHODS： 100 AMI patients were randomly divided into control group and observation group by parallel random sampling， 50 cases in each group. Control group was given conventional PCI， preoperatively chewing 300 mg aspirin+300 mg clopidogrel， postoperatively taking 100 mg/d aspirin+75 mg/d clopidogrel. Observation group was additionally treated 2-4 with Buchang naoxintong capsules （after bracket release）， 3 times a day， the treatment course for both groups was 7 d， observation period was 1 month. Infarct-related artery myocardial perfusion grade （TMPG） in 2 groups， platelet activation function indexes [CD62P， CD63 and monocyte platelet aggregation （MPA） positive expression rates] before and after treatment， the incidences of adverse cardiac events （MACE） and complications were observed and compared 15 min after PCI. Meanwhile， the incidence of adverse reactions was recorded. RESULTS： After treatment， the cases of TMPG perfusion grade 3 in observation group were significantly higher than control group， the incidence of MACE was significantly lower than control group， with statistical significance （P＜0.05）； there was no significant difference in the incidences of complications and adverse reactions in 2 groups （P＞0.05）. Before treatment， there was no obvious difference in CD62P， CD63， MPA positive expression rates in 2 groups； after treatment， CD62P， CD63， MPA positive expression rates in 2 group were significantly lower than before， and observation group was lower than control group， with significant differences （P＜0.05）. CONCLUSIONS： In PCI treatment of AMI patients， Buchang naoxintong capsule can rapidly improve platelet activation functions， TMPG perfusion， reduce the incidence of MACE， with good safety and no increase of complications.