Abstract: Objective: To study tumour-brain interface of meningioma WHO（2000） I on preoperative MR imaging as well as pathological appearance and clinical significance.Methods: In 30 cases CSF-vessel circum-interspace,peritumoral brain edema on MR imaging,and brain-tumor interfaces in operative performance（Ilden type） were prospectively studied.Biopsies from abnormal brain regions were sent for histological evaluation regarding the presence or absence of tumor invasion of brain.Results: Ildan types,the grade of peritumoral brain edema on T2WI,and CSF-vessel circum-interspace individually seemed to correlate very precisely with the invaded brain tissue by tumors（P＜0.05）,allowing the prediction of microsurgical effort required during surgery.Additionally,a positive correlation was found between the CSF-vessel circum-interspace and the types of cleavage（P＜0.05）. Conclusions: The extent of preoperative peritumoral brain edema and CSF-vessel circum-interspace may predict the types of cleavage and invasion of brain.