Objective To investigate the influencing factors for the formation of intracranial collateral circulation in patients with acute cerebral infarction （ACI）， and to establish a risk factor model.Methods A total of 100 patients with ACI who were admitted to our hospital from July 2020 to December 2021 were enrolled in this study， and according to the formation of intracranial collateral circulation， the patients were divided into non-collateral circulation group with 34 patients and collateral circulation group with 66 patients. A retrospective analysis was performed for their clinical data. Univariate analysis and multivariate logistic regression analysis were used to investigate the influencing factors for the absence of collateral circulation in ACI patients. A risk factor model was established， and the receiver operating characteristic （ROC） curve was plotted to investigate the value of the risk factor model in predicting the absence of intracranial collateral circulation in ACI patients.Results The multivariate logistic regression analysis showed that hypertension， smoking history， and increases in serum homocysteine （Hcy）， neutrophil-to-lymphocyte ratio （NLR） in whole blood， platelet-to-lymphocyte ratio （PLR） in whole blood， and serum neuron-specific enolase （NSE） were the risk factors for the absence of intracranial collateral circulation in ACI patients （odds ratio ［OR］ = 1.929， 2.361， 2.382， 2.375， 2.275， and 2.022， P<0.05）， and increases in serum high-density lipoprotein cholesterol （HDL-C） and basic fibroblast growth factor （bFGF） were protective factors against the absence of intracranial collateral circulation in ACI patients （OR=0.446 and 0.517， P<0.05）. The above factors were included in the risk factor model of logit（P）=-15.173 + hypertension×0.657 + smoking history×0.859 - HDL-C×0.807 + Hcy×0.868 + NLR×0.865 + PLR×0.822 - bFGF×0.659 + NSE×0.704， and the ROC curve was plotted. The results showed that when logit（P）>15.46， the area under the ROC curve was 0.883， with a diagnostic sensitivity of 88.0% and a specificity of 80.0%.Conclusions The absence of intracranial collateral circulation in ACI patients is closely associated with hypertension， smoking history， increases in serum Hcy and NSE， increases in NLR and PLR in whole blood， and reductions in serum HDL-C and bFGF， and the risk factor model established based on these factors has a high value in predicting the absence of intracranial collateral circulation in ACI patients. Corresponding intervention strategies should be adopted for high-risk patients to improve prognosis. ［Journal of International Neurology and Neurosurgery, 2022, 49(6): 13-17］