Aim To investigate the effect of renin-angiotensin system inhibitor (RASI) on long-term prognosis in patients with coronary heart disease (CHD) after contrast-associated acute kidney injury (CA-AKI). Methods A total of 1 526 patients with CHD diagnosed by coronary angiography and postoperative CA-AKI in Guangdong Provincial People's Hospital from January 2008 to December 2018 were included in this study. They were divided into RASI group (n＝984) and non-RASI group (n＝542) according to whether they took RASI or not. The primary end point was long-term all-cause death. Baseline clinical data were compared between the two groups. Kaplan-Meier method and COX regression analysis were used to evaluate the effect of RASI on long-term prognosis. Results The proportion of β-receptor blockers and statins used in the RASI group was higher than that in the non-RASI group (P＜0.01). During the median follow-up period of 4.75 years (quartile 2.82 years, 6.67 years), 332 patients died, and the all-cause mortality was 21.76%. Kaplan-Meier survival analysis showed that the mortality of RASI group was lower than that of non-RASI group (P＝0.001). Univariate and multivariate COX regression analysis showed that RASI treatment after discharge was significantly negatively correlated with all-cause death (P＝0.001, P＝0.034), and RASI was an independent protective factor for long-term all-cause death. Conclusions RASI is an independent protective factor for the long-term prognosis of CHD patients after CA-AKI. Long-term use of RASI therapy can reduce the all-cause death in patients with CHD and CA-AKI.