Abstract: Objective: To analyze the relationship between MRI and vascular score of MRA in adult Moyamoya disease (MMD), and to provide a theoretical basis for the clinical intervention of MMD. Methods: Analyze the clinical data of 50 adult patients with MMD performed by MRI and MRA. According to the Houkin`s rating method, MRA was performed on each side of the cerebral hemisphere, and the number of Moyamoya vessels (MMV) was also scored. The correlations between brain MRI manifestations (cerebral hemorrhage, cerebral ischemia, cerebral softening and brain atrophy) and MRA classification and MMV score were evaluated. Results: There were significant differences in cerebral hemorrhage and cerebral ischemia between different MRA classifications (χ²=13.04,P=0.005;χ²=8.21,P=0.04). The incidence of cerebral hemorrhage in patients with MRA grade II and III is higher, and the incidence of acute cerebral infarction in patients with grade I and IV is higher. There were significant differences in cerebral hemorrhage and cerebral softening between different MMV scores (χ²=24.79,P<0.001;χ²=11.42,P=0.02). The incidence of cerebral hemorrhage in patients with MMV scores 4, 5 points was higher, and the incidence of cerebral softening was higher with 1, 2 points. Conclusion: The MRA classification and the formation of MMV suggest the occurrence of cerebrovascular events in MMD to some extent, and preliminarily predict the possibility of cerebrovascular events, which can provide guidance for clinical prevention of cerebrovascular events in MMD.