Ischemic stroke, which is due to the occlusion of a cerebral blood vessel, comprises nearly 80-90% of all strokes. Currently, reperfusion of the salvageable tissue via thrombolytic drug or endovascular treatment is the most effective strategy to reduce brain damage. However, after recanalizing the occluded vessels, subsequent reperfusion injury is inevitable. It may not only weaken the therapeutic effects of timely reperfusion but also impede patients' recovery. Moreover, thousands of neuroprotective drugs effective in experimental models have been proved to be unsuccessful in clinical trials. Therefore, effective strategies are urgently needed to prevent and treat cerebral reperfusion injury and further improve the prognosis of acute ischemic stroke. Researchers applied remote ischemic conditioning to mouse model of focal cerebral reperfusion injury and found that it could reduce cerebral infarct size. And clinical researches demonstrated that remote ischemic conditioning was an effective strategy to improve cerebral perfusion and prevent recurrent stroke in patients with ischemic stroke. However, whether remote ischemic conditioning is safe and effective in protecting patients with large-vessel ischemic stroke and undergoing endovascular treatment is still unclear. The investigators' hypothesis is that RIC is a safe and effective strategy to reduce brain injuries in stroke patients undergoing endovascular treatment.