Background: The balloon-guiding catheter (BGC) reportedly reduces the number of retrievals and occurrence of distal emboli,achieving superior revascularization results and improved clinical outcomes in acute stroke.This study will aim to examine the efficacy and safety of the new SeparGateTM BGC.Design: This prospective multicenter single-ann clinical trial will aim to include 128 patients who fulfill its inclusion and exclusion criteria.All patients will receive endovascular interventional therapy with BGC assistance.The primary endpoint will be the immediate surgical success rate,while the secondary endpoint will be product performance.The safety evaluation will include serious adverse events such as puncture site hematoma and bleeding,cerebral vasospasm,vessel dissection,vessel perforation,air embolism,thrombus (acute or subacute),vessel occlusion,distal embolization,infection,adverse reaction to anfiplatelet and anticoagulant drugs,intracranial hemorrhage,stroke,death,and device defect.Discussion: The prospective multicenter trial will provide safety and efficacy information for the SeparGateTM BGC.Its findings will provide a clinical reference for endovascular adjuvant therapy of cerebrovascular disease.Trial registration.: ChiCTR1800014459.