Objective To observe distribution rules of angiotensin converting enzyme（ ACE） gene polymorphism in patients with unstable angina pectoris according to different TCM syndrome and coronary artery plaque characteristic.Methods Collected 240 cases of patients suffering from unstable angina pectoris

with 38 cases of Qi-deficency and blood-stasis syndrome

24 cases of Qi-stagnation and blood-stasis syndrome

19 cases of phlegm blocking heart vessel syndrome

39 cases of heart blood stasis syndrome

18 cases of Yin-cold stagnation syndrome

23 cases of Qi and Yin deficiency syndrome

32 cases of heart and kidney Yin deficiency syndrome

47 cases of vital energy faded syndrome.Besides

collected 60 cases of healthy volunteers as control group. Adopted polymerase chain reaction（ PCR）technique to examine its ACE allele inserting / deleting（ I / D） and ACE genotype. Adopted Multi-slice helical CT the evaluate the degree of coronary artery plague hardening. Analyzed distribution rules of ACE gene polymorphism of patients suffering from unstable angina pectoris according to different TCM syndrome and coronary artery plaque characteristic. Results There were 120 cases of coronary artery soft plaque

54 cases of medium density plaque

66 cases of calcified plaque in 240 cases of patients suffering from unstable angina pectoris. There were 32. 9%（ 79cases） ACE-DD genotype in patients suffering from unstable angina pectoris

remarkably superior to 15%（ 9 cases）in healthy volunteers（ P < 0. 05）; There were 54. 2%（ 130 cases） D allele in patients suffering from unstable angina pectoris

remarkably superior to 46. 7%（ 28 cases） in healthy volunteers（ P < 0. 05）; DD genotype obviously had more people in Qi-deficency and blood-stasis syndrome

phlegm blocking heart vessel syndrome

heart blood stasis syndrome than in healthy volunteers（ P < 0. 01）. ACE-ID genotype obviously had more people in blood-stasis syndrome

Qi and Yin deficiency than in healthy volunteers（ P < 0. 01）. D allele chromosome number in patients of heart blood stasis syndrome

phlegm blocking heart vessel syndrome

Qi and Yin deficiency syndrome was remarkably more than that in healthy volunteers（ P < 0. 01）. The percentage of ACE-DD genotype took in coronary artery soft plaque and medium density plaque patients was more than that in calcified plaque patients（ P < 0. 05）. Conclusion ACE gene DD genotype and D allele may be the susceptibility gene of coronary heart disease unstable angina pectoris

and had more patients in Qi-deficency and blood-stasis syndrome

phlegm blocking heart vessel syndrome

heart blood stasis syndrome. ACE-DD genotype had more patients in soft plaque and medium density plaque.