The prognosis of unstable angina pectoris (UAP) differs from non-ST-segment elevation myocardial infarction, and percutaneous coronary intervention (PCI) is considered to improve outcomes of UAP. This study aimed to assess the prognostic value of uric acid to albumin ratio (UAR) for long-term mortality in UAP patients after PCI. Our study retrospectively enrolled 2298 patients hospitalized because of UAP in a tertiary hospital. Divided by medium UAR, the patients were classified into two groups. Baseline demographics, clinical features and laboratory characteristics were obtained from medical records. Post-discharge follow-up was performed either in outdoor clinic or through phone call. The primary endpoint in this study was cardiac death, while all-cause death and rehospitalization were designated as the secondary endpoints. The median follow-up time was 672 days. Among all patients, 58 (2.5%) died, 28 of which died of cardiac deaths (1.2%), and 467 were re-hospitalized (20.3%). Cardiac mortality and all-cause mortality were found to be significantly higher in the high UAR group than in the low UAR group (p = 0.007, p < 0.001), and Kaplan-Meier analysis showed patients with higher UAR may suffer from worse outcomes (p = 0.020). UAR, PCI history, and age were identified as independent predictors of cardiac mortality by multivariate Cox regression. A UAR value of >8.35 was demonstrated as an ideal cut-off point to predict post-PCI cardiac mortality (p <0.001). Overall, it is indicated that baseline UAR was independently correlated with long-term cardiac mortality in patients with UAP treated by PCI.