Objective To investigate the correlation between modality of the circle of Willis (COW)and acute cerebral stroke (AIS) in patients without carotid artery(CA) stenosis or occlusion. Methods The modality of COW in 75 patients with AIS were retrospective analyzed and divided into 35 patients with AIS had severe CA stenosis (group I)and 45 without (group II) according to CA stenosis, and 35 patients without cerebral infarction patients (Group III) were compared. Variables including the state type of COW, vascular development, feeding artery disease were analyzed by χ2 test and Bonferroni correction χ2 test. The relationship between AIS and vascular development were analyzed by pearson correlation analysis. Logistic regression was used to estimate potential risk factors for AIS. Results The differences of Three groups in COW state type and anterior communicating artery(ACoA), A1 segment of the anterior cerebral artery(ACA-AI), P1 segment of the posterior cerebral artery (PCA-PI) dysplasia ,and the number of intracranial artery stenosis were statistically significant (χ2=15.84, 79.24, 16.19, 64.19, P<0.05).There was no significant difference between group I and II in the factors (χ2=0.68, 3.89, 1.81, 3.89, P﹥0.05). OR in incomplete COW, ACoA and PCOA variation were 0.01, 6.55, 3.19;95%CI:0.00-0.22, 1.69-25.44, 1.41-9.60. Conclusion In the absence of CA severe stenosis, the incomplete COW, the variation of ACoA and PCOA were still potential risk factors for AIS.