To investigate the relation of higher apolipoprotein B/apolipoprotein AI (apoB/AI) ratio with the risk of suffering intracranial atherosclerotic stenosis (ICAS) in both stroke and non-stroke population, we enrolled 1138 patients with acute ischemic stroke (359 with ICAS, 779 without ICAS) and 1072 non-stroke controls (239 with ICAS, 833 without ICAS) into the study. ICAS was defined as atherosclerotic stenosis >50% or the occlusion of the several main intracranial arteries. ApoB/AI ratio of patients with ICAS was significantly higher than those of individuals without ICAS in both stroke group and non-stroke groups. Increased ratio of apoB/AI was an independent risk factor for ICAS in both stroke group (OR 2.80, 95% CI 1.45-5.42, p=0.002) and non-stroke groups (OR 3.38, 95% CI 1.61-7.12, p<0.001). Compared with the lowest quartile, the third (Stroke OR=1.71, 95%CI, 1.11-2.63, p=0.014; Non-stroke OR=1.71, 95%CI, 1.04-2.82, p=0.033) and forth quartiles (Stroke OR=2.06, 95%CI, 1.27-3.35, p=0.003; Non-stroke OR=2.00, 95%CI, 1.16-3.49, p=0.012) were independent risk factors for ICAS in both stroke (p value for trend=0.001)) and non-stroke (p value for trend=0.006) groups. In summary, increased apoB/AI ratio was a valuable independent risk factor for ICAS in stroke patients as well as in non-stroke controls.