General inclusion criteria：  18 years old or more; NIHSS≥6 during randomization; Pre-onset MRS < 2; Acute ischemic stroke was diagnosed; Within 24 hours from the onset of stroke to the completion of femoral artery puncture, regardless of whether intravenous thrombolysis has been performed;The time point of stroke onset was defined as the time point at which the patient's last normal condition was known; The subject (or his/her guardian) agrees to participate in this study and signs the informed consent.  Image inclusion criteria：  When it is less than 6h (inclusive) from the onset of stroke to the completion of femoral artery puncture, patients should be examined by cranial CT or MR; When it is more than 6h but less than 24h (inclusive) from the onset of stroke to the completion of femoral artery puncture, brain CT or MR should be performed and Aspects ≥6 points should be satisfied.(If immediate CT perfusion imaging or MR perfusion imaging is feasible, CTP or MRP is recommended to assist in the assessment of the infarct core, and Aspects ≥6 points shall also be satisfied); DSA angiography showed acute intracranial arterial occlusion, including intracranial segment of internal carotid artery (C4-C7), middle cerebral artery (M1/M2), basilar artery and intracranial segment of vertebral artery (V4).  General exclusion criteria：  Neither MRI nor CT can be performed; Hemorrhagic stroke or major ischemic stroke within 6 months before enrollment; Severe persistent hypertension that cannot be controlled by venous hypotension, i.e., patients with SBP persistent >185mmHg and/or DBP persistent >110mmHg; Suppose septic emboli or suspected bacterial endocarditis; Renal failure, defined as: creatinine >3.0mg/dL(264 mol/L); Blood glucose < 2.78mmol/L (50mg/dL) or >22.20mmol/L (400mg/dL); decreased platelet count (< 40×109/L); Known bleeding tendency, defect of coagulation factor, taking anticoagulants and INR > 3.0; Pregnant or lactating women; known to be severely allergic to contrast agents and known to be allergic to nickel materials; The presence of diseases that may affect the assessment of neurological function (such as neurological diseases, mental diseases, etc.); with heart, lung, liver function failure or other serious diseases to interventional surgery; Participating in clinical trials of other drugs or devices; Life expectancy less than 6 months; Other conditions judged by the researcher to be unsuitable for inclusion.  Image exclusion criteria：  CT or MR imaging evidence of intracranial hemorrhage or known bleeding tendency; CT/MR/DSA showed > occlusion (such as bilateral internal carotid artery occlusion at the same time, or anterior circulation and posterior circulation intracranial vessels occlusion at the same time, or internal carotid intracranial and extracranial segments occlusion at the same time); Carotid artery dissection, carotid initial occlusion or arteritis; The vascular circuitry was severe, and the intracranial thrombectomy stent was difficult to reach the target position.