Background Whether ASPECTS 5 and ASPECTS 6 were significantly different on clinical outcomes in acute anterior circulation ischemic stroke undergoing endovascular treatment remains unclear. We aimed to retrospectively compare the effectiveness and safety of ASPECTS 5 and ASPECTS 6 in acute anterior circulation large-artery occlusive stroke patients. Methods A total of 41 patients, 14 in the ASPECTS 5 group and 27 in the ASPECTS 6 group, were enrolled between January 2014 and June 2016. Modified Rankin Scale 0–2 was considered as good functional outcome. Symptomatic intracerebral hemorrhage at 72 hours and mortality at 90 days were recorded. Results Good functional outcome at 90 days in the ASPECTS 5 group (0% (0/14)) was significantly lower than that in the ASPECTS 6 group (25.9% (7/27)) ( p = 0.04). Rates of symptomatic intracranial hemorrhage (21.4 (3/14) vs 18.5% (5/27), p = 0.83) and mortality (64.3% (9/14) vs 44.4% (12/27), p = 0.23) within 90 days were not significantly different. There is a trend for a lower rate of successful reperfusion in the ASPECTS 5 group (71.4% (10/14) for ASPECTS 5 vs 92.6% (25/27) for ASPECTS 6, p = 0.07). Conclusions ASPECTS 5 has very little chance to reach good functional outcome in Chinese patients with anterior circulation large-artery occlusive stroke. Future studies with large sample sizes are needed.