The present study evaluated the clinical results of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) treatment in patients with unstable angina (UA) with preserved left ventricular systolic function who underwent percutaneous coronary intervention (PCI) due to uncertainty regarding the long-term prognosis using ACEI or ARB. A total of 1627 UA patients with preserved left ventricular systolic function after PCI were enrolled. After propensity score matching, there were no differences in major adverse cardiovascular and cerebrovascular events (MACCEs) (hazard ratio (HR) = .860, 95% confidence interval (CI): .465–1.590, P = .630), all-cause death (HR = .334, 95% CI: .090–1.238, P = .101), nonfatal myocardial infarction (HR = 4.929, 95% CI: .576–42.195, P = .145), stroke (HR = 1.049, 95% CI: .208–5.290, P = .954) and target vessel revascularization (TVR) (HR = 1.276, 95% CI: .537–3.031, P = .581) between the ACEI and ARB groups. In conclusion, prognoses were comparable between ACEI or ARB treatment in UA patients who had preserved left ventricular systolic function after PCI.