Vascular recanalization therapy is the major treatment strategy for acute ischemic stroke with large vessel occlusion (AIS-LVO). Time window for mechanical thrombectomy has been proven to be within 6 h after stroke onset. Screening of patients who are to undergo mechanical thrombectomy 6-24 h or beyond 24 h after onset remains controversial. In this review, we summarize the current status of mechanical thrombectomy in AIS-LVO patients with extended time window of 6-24 h or beyond 24 h, and analyze the feasibility and evaluate the strategies for extending the time window of thrombectomy.