Objective To investigate the value of serum C reactive protein (CRP), apolipoprotein A1 (ApoA1), and CRP to ApoA1 ratio (CRP/ApoA1) in evaluating coronary artery disease. Methods A total of consecutive 533 patients who were hospitalized due to chest pain and examined by coronary angiography in the No. 904 Hospital of Joint Logistics Support Force of PLA from Dec. 2018 to Dec. 2019 were retrospectively included. According to the Gensini score and coronary angiography results, the patients were divided into normal coronary artery group (Gensini score of 0, n=118), coronary atherosclerosis group (Gensini score of 1-18 but not meeting the diagnostic criteria of coronary heart disease[CHD], n=109) and CHD group (Gensini score of 1-180 and meeting the diagnostic criteria of CHD, n=306). According to the Gensini score, the CHD patients were divided into mild CHD group (Gensini score of 1-<30, n=177) and severe CHD group (Gensini score of 30-180, n=129). According to the lesion vessel number, the CHD patients were divided into single-vessel lesion group (n=147), double-vessel lesion group (n=90) and 3 or more vessel lesion group (n=69). The hematological indexes such as serum CRP, ApoA1 and albumin were recorded in each group, and CRP/ApoA1 was calculated. Multivariate logistic binary regression analysis was used to determine the independent risk factors of CHD and severe CHD. Receiver operating characteristic (ROC) curve was used to analyzed the predictive value of CRP/ApoA1 on CHD, severe CHD and 3 or more vessel lesions, and the differences from CRP to albumin ratio (CAR), CRP and ApoA1 were observed. Results The CRP/ApoA1 of the CHD group was significantly higher than that of the normal coronary artery group (P<0.01), and the CRP/ApoA1 of the severe CHD group was significantly higher than that of the mild CHD group (P<0.01). Multivariate logistic binary regression analysis suggested that CRP/ApoA1 was an independent risk factor of CHD and severe CHD (odds ratio[OR]=2.171, 95% confidence interval[CI] 1.293-3.647, P<0.01; OR=6.306, 95% CI 3.591-11.073, P<0.01). Spearman correlation analysis showed that CRP/ApoA1 was positively correlated with Gensini score (r=0.419, P<0.01) and lesion vessel number (r=0.431, P<0.05). ROC curve analysis showed that CRP/ApoA1 had good predictive value for CHD, severe CHD and 3 or more vessel lesions (area under curve[AUC]=0.704, 0.796 and 0.820), and was significantly better than that of CAR, CRP and ApoA1 (AUC=0.684, 0.783, 0.806; 0.682, 0.778, 0.800; and 0.641, 0.669, 0.687) (all P<0.05). Conclusion CRP/ApoA1 is related to CHD and its severity, and its diagnostic value is higher than that of CAR, CRP and ApoA1. It can be used in the diagnosis and evaluation of CHD.