Aim To explore the correlation between remnant cholesterol and severity of coronary artery stenosis in patients with prehypertension based on Gensini score. Methods The clinical data of 36 216 coronary angiography patients hospitalized in the Department of Cardiovascular Medicine of Northern Theater Command General Hospital from 2004 to 2014 were retrospectively analyzed, including 421 patients with prehypertension. There were 85 patients with Gensini score ≥20, and 85 patients with Gensini score <20 in this cohort were selected as the control group. The clinical characteristics of the two groups were observed and the relationship between remnant cholesterol and common blood lipid indexes and the degree of coronary artery stenosis in prehypertensive patients was investigated. The seventh report of the National Joint Committee on the prevention, detection, evaluation, and treatment of hypertension in the United States defines prehypertension as systolic blood pressure of 120 to 139 mmHg(1 mmHg＝0.133 kPa) and/or diastolic blood pressure of 80 to 89 mmHg. The European Atherosclerosis Society (EAS) defines remnant cholesterol as total cholesterol－(high density lipoprotein cholesterol＋low density lipoprotein cholesterol). Remnant cholesterol is the amount of cholesterol in triglyceride-rich lipoprotein. Results In the Gensini score≥20 group, the proportion of diabetic patients and left ventricular ejection fraction were higher than those in the Gensini score＜20 group, the difference was statistically significant (P＜0.05). In terms of lipid-related indicators, the levels of remnant cholesterol, triglyceride and total cholesterol in Gensini score≥20 group were higher than those in the Gensini score＜20 group, the differences were statistically significant (P＜0.05). The correlation analysis of remnant cholesterol and triglyceride in Gensini score≥20 group was conducted. The results showed that there was a correlation between remnant cholesterol and triglyceride (r＝0.535, P＜0.01).Subsequently, patients with triglyceride≥1.7 mmol/L were screened for further correlation analysis, and the results showed that the correlation between remnant cholesterol and triglyceride increased further (r＝0.625, P＜0.01). Logistic regression showed that remnant cholesterol (OR＝8.0,5%CI:2.87～27.53, P＜0.01), low density lipoprotein cholesterol (OR＝3.6,5%CI:1.93～6.57, P＜0.01) and diabetes mellitus (OR＝2.4,5%CI:1.10～5.00, P＜0.05) were significantly associated with severe coronary artery stenosis. Conclusion Remnant cholesterol, low density lipoprotein cholesterol, diabetes mellitus and other factors are closely related to the occurrence of severe coronary artery stenosis in patients with prehypertension complicated with coronary heart disease.