[Objective]To investigate the related risk factors of unstable plaques in extracranial carotid arteries in patients with ischemic cerebrovascular diseases(ICVD).[Methods] Two hundred and eight ICVD patients were enrolled and plaques in extracranial carotid arteries were detected by c(a)rotid color ultrasound.All the patients were divided into unstable plaque group(75 cases)and stable plaque group (133 cases)according to the ultrasound performance.Related disease history and the traditional risk factors of ICVD were recorded.The risk factors with statistical significance were screened out by univariate nonconditional Logistic regression analysis,and then the independent risk factors of unstable plaques in extracnmial carotid arteries were analyzed by multivariate non-conditional Logistic regression analysis.[Results]Univariate non-conditional Logistic regression analysis showed that male,history of hypertension,history of diabetes,smoking were positively correlated with the formation of unstable plaques in extracranial carotid arteries(P＜0.01 or ＜0.05).High density lipoprotein cholesterol(HDL-C)was negatively correlated with the formation of unstable plaques in extracranial carotid arteries(P＜0.01).There were no statistical significance in history of coronary heart disease,law of life,family history of hypertension,drinking,family history of stroke and low density lipoprotein cholesterol between two groups(p ＞0.05).Multivariate non-conditional Logistic regression analysis showed that male,history of hypertension,history of diabetes and smoking were the independent risk factors of the formation of unstable plaques in ex tracranial carotid arteries (OR =2.33,7.16,6.15,2.28,respectively,P＜0.01).And HDL-C was the protection factor of the formation of unstable plaques in extracranial carotid arteries(OR=0.84,P ＜ 0.01).[Conclusions] The independent risk factors of the formation of unstable plaques in extracranial carotid arteries in patients with ICVD are male,history of hypertension,history of diabetes and smoking.And HDL-C is the protection factor of the formation of unstable plaques in extracranial carotid arteries in patients with ICVD.It has important significance to take out necessary intervention for patients with risk factors.