Objective: To investigate the effect of early use of brain natriuretic peptide (BNP) on vascular endothelial function and ventricular structure in patients with acute myocardial infarction (AMI). Methods: A total of 96 AMI patients who received emergency PCI in our hospital from August 2018 to May 2020 were selected and randomly divided into control group and recombinant human brain natriuretic peptide (rhBNP) group, 48 cases in each group. Both groups were given basic drug therapy according to AMI guidelines, and rhBNP group was given rhBNP treatment early after PCI. The brachial artery flow mediated dilation (FMD), nitric oxide (NO), endothelin-1 (ET-1), left ventricular end diastolic volume (LVEDV) and left ventricular ejection fraction (LVEF), left ventricular remodeling (LVR) and incidence of cardiovascular adverse events were recorded 6 months after PCI. Results: After 2 weeks of treatment, FMD and NO levels in the rhBNP group were higher than those in the control group, and ET-1 level in the rhBNP group was lower than that in the control group (all P<0.05). The incidence of LVEDV, LVR and cardiovascular adverse events in the rhBNP group were lower than those in the control group at 6 months after PCI, and LVEF was higher than that in the control group (all P<0.05). Conclusion: Early use of BNP after emergency PCI can improve vascular endothelial function and ventricular structure, and reduce LVR and cardiovascular adverse events.