Aim: To determine angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymoprnhism in patients with coronary heart disease (CHD) and its relation with serum ACE levels.Methods: ACE genotypes of 6l patients with CHD and 63 healthy people were detected by PCR, and their serum ACE levels were concomitantly measured by microcolorimetric assay.Results: The frequency of DD genotype in patients with CHD was significantly higher than that in control group apd patients with DD genotype have higher serum ACE levels.Conclusion: ACE gene polymorphism is closely related to serum ACE level and DD genotype of ACE gene may be the independent risk factor of coronary heart disease in Chinese.