Purpose The study explored the association of waist circumference (WC) with the severity of cardiovascular diseases and hospital readmission of coronary artery disease (CAD) patients with normal body mass index (BMI). Patients and Methods 213 female and 431 male normal-BMI CAD patients were enrolled and assigned in three groups based on their gender-specific WC tertiles. Their cardiovascular risk factors and coronary angiography characteristics were analyzed in a cross-sectional study, and the gender-specific relationship between WC and one-year re-admission rate was prospectively explored. Results The cross-sectional analysis showed that for male normal-BMI CAD patients, diabetes and dyslipidemia prevalence, Apo B/A1, hs-CRP, and uric acid levels triglycerides-glucose index, the incidence of left main disease, three vessel disease, calcification lesion, total occlusive lesion, and complex lesion, as well as Gensini score was in the order of WC tertile 3 > WC tertile 2 > WC tertile 1. In addition, male normal-BMI CAD patients in the highest WC tertile were at an increased risk of severe CAD (OR=2.21), and the correlation was still statistically significant even after adjusting for potential cardiovascular risk factors (OR=1.87). For female normal-BMI CAD patients, as the WC tertiles increased, uric acid level, the prevalence of three vessel disease, diffuse lesion, and complex lesion gradually increased ( P <0.05), but no significant difference was found in the risk of severe CAD among different WC groups (all P >0.05). Prospective analyses showed that the higher the WC tertile was, the higher the one-year re-admission rate in men, but not in women, and after adjusting for other risk factors, men with the highest WC tertile showed more than twice the risk of patients with the lowest WC tertile. Conclusion Male but not female, normal-BMI CAD patients with increased WC had more severe CAD and a higher risk of one-year re-admission rate.