Aim To explore the association between 4A4B insert/deletion polymorphism of endothelial nitric oxide synthase(eNOS) and coronary heart disease. Methods Genotypes of 4A4B locus were detected in 842 coronary heart disease patients and 842 age and gender matched healthy individuals using polymerase chain reaction and Gel electrophoresis and the association between them was analyzed. Results The frequency distributions of patients with smoking, diabetes, hypertension, obesity and lipid metabolic abnormity were significantly higher than those in controls. Genotype distributions in controls were in consistence with Hardy-Weinberg inheritance model. Allele 4A(10.2% vs. 6.9%, OR＝2.03, 95%CI＝1.39~2.44), genotype AA(3.0% vs. 0.9%, OR＝2.08, 95%CI＝1.45~2.67) and AA＋AB(17.4% vs. 13.1%, OR＝1.58, 95%CI＝1.08~1.94) of the locus were significantly associated with conorany heart disease. Stratifiying analysis results showed that genoytpe AA and 4A allele were significantly associated with the disease in each subgroup excluding non-drinking subgroup, respectively, and the disease risk of individuals carring AA genotype and 4A allele were 2.34, 2.59, 3.13 fold and 2.55, 2.77, 3.10 fold than those with BB genoytpe or 4B allele in diabetes, hepertension, and fact subgroups, respectively. Conclusions 4A allele and AA, AA＋AB genotypes of 4A4B locus within eNOS gene might be genetic susceptible factors for coronary heart disease, and these genetic factor of the locus could interact with status of smorking, drinking, diabetes, hypertension and fat to further increase susceptibility to the disease.