Objective:To investigate the correlation between collateral flow compensation mode and interventional treatment decision in patients with severe bilateral internal carotid artery stenosis/occlusion.Methods:According to the location of internal carotid artery lesions, patients with severe stenosis/occlusion of bilateral internal carotid artery were selected at the Second Affiliated Hospital, Qiqihar Medical University and the Sixth Medical Center of PLA General Hospital from May 2017 to June 2020.Results:A total of 42 patients were finally enrolled and divided into 4 types, including 34 males and 8 females with median age 61±8(48-82)years. The collateral circulation pathways manifested as following modes: anterior communicating artery collateral, posterior communicating artery collateral, ophthalmic artery collateral, posterior cerebral middle cerebral artery pial anastomosis collateral, posterior choroidal artery anterior choroidal artery collateral, external carotid internal carotid artery C4 segment collateral, pericallosal artery anastomosis collateral, dural and pial collateral and neovascularization. Type Ⅰ severe stenosis/occlusion of C1 segment was found in 20 cases (47.6%). There were 5 cases (11.9%) of type Ⅱ severe stenosis/occlusion from C2 to C6 prior to ophthalmic artery branch. Type Ⅲ severe stenosis/occlusion occurred in 2 cases (4.8%) after the split of ophthalmic artery. Type Ⅳ was mixed type in 15 cases (35.7%).Conclusions:The compensatory pathway of collateral circulation is closely related to the lesion location. To explore the compensatory pattern of collateral circulation is helpful for clinicians to accurately analyze the lesion characteristics and guide individualized interventional therapy.