Inclusion Criteria:  Aged ≥ 18 years and ≤ 85 years; Symptoms and signs in accordance with anterior circulation ischemia and large vessel occlusion (ICA, MCA-M1 or M2) confirmed by DSA; Premorbid modified Rankin Scale(mRS)<2 and Pre-operation NIHSS score ≥6;  The patients should receive endovascular treatment within 24 hours:  If the treatment could happen within 6 hours, the patient should have an CT or MR If the treatment could happen 6-24 hours, the patient should have an CT or MR, have an ASPECTS ≥ 6 points. If immediate CT perfusion imaging or MR perfusion imaging is feasible, CTP or MRP should be performed at the same time to assist in the evaluation of the infarct core. Written informed consent obtained from patient or patient's legally authorized representative.  Exclusion Criteria:  Large (more than one-third of the MCA) regions of clear hypodensity on the baseline neuroimaging or significant mass effect with midline shift; Any type of intracranial hemorrhage or subarachnoid hemorrhage (only microbleeds are allowed, or judge from surgeon's clinical experience) by neuroimaging; Proven Simultaneous acute occlusion of both carotid artery systems, and Proven tandem lesion of simultaneous occlusion of intracranial and extracranial vessels by neuroimaging; Occlusion of the common carotid artery,and known or suspected chronic occlusion of target vessel; Patients with consciousness disorder with posterior circulation vascular occlusion, NIHSS score is 3 points (1a=3); Proven intracranial artery occlusion due to arterial dissection or arteritis by neuroimaging; Arterial tortuosity and other problems that would prevent the device from reaching the target vessel; Known to have one or more of the following allergies/resistances or contraindications: antiplatelet drugs/anticoagulant drugs/contrast agents and/or anesthetics; Known allergies to medical devices and related products (allergy to materials such as nickel-titanium metal or its alloys); Active bleeding or known bleeding tendency (such as: anticoagulant therapy or coagulation dysfunction before surgery, INR>3.0); Baseline platelet counts<40×10^9/L; Severe heart, liver or kidney failure and other serious or terminal illness; Accompanied by ST-segment elevation myocardial infarction or severe infection (endocarditis or sepsis); Hypertension that cannot be controlled after treatment (Baseline blood pressure>185/110 mmHg); Baseline blood glucose < 2.7 or > 22.2 mmol/L. after treatment; Life expectancy less than 3 monthes; Women who are pregnant or planning to pregnancy during half a year by taking medical history); Dementia or psychiatric disease that would confound the neurological or functional evaluations; Current participation in another drug or device research; Other special situations which the researchers believe to be not suitable for enrollment.