Abstract: To investigate the pathogenesis of the recurrence of meningiomas operated by Simpson Grade I resection. Methods :The clinical,Gadolinum-enhance MRI,CT scan,pathology and the resection area were utilized to analysis the pathgesis of the recurrence of brain convexity meningiomas after total resection. Results :The dural area by meningiothelioma cell infiltration is larger than CT scan and Gadolinumenhance MRI,and the basic reason of recurrence of meningiomas is the less resect area of dural matter. Conclusion :Based on the operation by Simpson Gr-ade I resection,it can prevent the recurrenece of tumor effectively by resect the dural"tail"on Gaolinumenhance MRI+0.3cm,or the dural and vein-sinus away from the infiltrated area +0.5cm.