Objective To analyze the high-resolution magnetic resonance imaging features and differential diagnosis of moyamoya disease (MMD) and middle cerebral artery stenosis (ICAD). Methods Fifty patients with MMD and 50 patients with ICAD were respectively included in the control group and observation group. Both groups underwent vascular wall high-resolution magnetic resonance imaging (HR-MRI) examination. The outer diameter and outer edge area of stenotic vascular wall of middle cerebral artery (MCA) showed by HR-MRI, type of stenosis (eccentric/concentric), signal intensity of tube wall (homogeneous or not) and the formation rate of collateral vessels around the stenosis segment were compared between the two groups. The efficiency (sensitivity specificity, accuracy) of outer diameter and outer edge area of stenotic vascular wall in the diagnosis of MMD and ICAD was analyzed. Results The outer diameter and outer edge area of stenosis segment vascular wall in the observation group [(3.04±0.28)mm, (7.18±1.45) mm2 ] were larger than those in the control group [(1.76±0.42)mm, (2.72±1.61)mm2 ] (P<0.05); In the observation group, there was eccentric stenosis in 44 cases (88.00%) and concentric stenosis in 6 cases (12.00%), while in the control group, there were 27 cases (54.00%) and 23 cases (46.00%), respectively. The rate of inhomogeneous vascular wall signal in the observation group (84.00%) was higher than that in the control group (48.00%) while the formation rate of collateral vessels around the stenosis segment in control group (86.00%) was higher than that in the observation group (50.00%) (all P<0.05); The sensitivity and accuracy of outer diameter and outer edge area of stenosis segment vascular wall in the diagnosis of ICAD (90.48%, 86.00%) were significantly higher than those in the diagnosis of MMD (72.50%, 68.00%) (P<0.05). Conclusion The HR-MRI features of MMD and ICAD are different. The outer diameter and outer edge area of stenotic vascular wall, stenosis type, lumen signal intensity and formation of collateral vessels around the stenosis segment can be used as a diagnostic point.