Objective To investigate the relationship between angiotensin converting enzyme(ACE) gene polymorphism and carotid plaque composition,vessel wall morphology,and clinical symptoms based on vessel wall magnetic resonance imaging. Methods Totally 75 hypertensive patients(75 internal carotid artery plaques) with maximum plaque thickness≥1.5 mm,according to the ACE insertion(I) or deletion(D) gene polymorphism,were divided into ACE 2 genotype group(n=37) and ACE ID/DD genotype group(n=38). The influences of plaque composition,vessel wall morphology,clinical symptoms,and use of ACE inhibitor or angiotensin receptor blocker(ACEI/ARB) on vessel wall morphology were analyzed. Results Compared with ACE 2 genotype group,the ACE ID/DD genotype group had significantly higher incidence of ischemic stroke(Χ2=3.921,P=0.048). The plaque composition and vessel wall morphology showed no significant difference between these two groups. Inside ACE ID/DD genotype group,the carotid remodeling index was significantly lower in users of ACEI/ARB than non-users of ACEI/ARB(1.85±0.60 vs. 2.48±0.40;t=3.854,P=0.001).Conclusion In primary hypertension,ACE ID/DD genotype may be associated with carotid atherosclerotic plaque.