Abstract： Objective To evaluate the impact of high-field intraoperative magnetic resonance imaging (iMRI) on extension of resection and surgical strategy modification for glioma surgery. Methods One hundred and six patients, admitted to our hospital from October 2009 to June 2010, were performed glioma resections with the help of high-field iMRI. Questionnaires were filled and collected prospectively to record the surgeons' intention on the extent of resection (EoR) and the intra-operative estimation of EoR before every iMRI scan. The scan imagings were collected based on the request of the surgeon, and the percentage of tumor removal was calculated according to the iMRI data. The impact of iMRI on the tumor EoR and modification of surgical strategy was then evaluated. Results Preoperatively, 48 patients were intended to achieve total tumor removal, 41 sub-total tumor removal, and 17 partial removal. The first intraoperative MRI scan revealed that 42 (39.6%) patients achieved complete resection, while residual tumors were depicted in 64 (60.4%).Further tumor resections were performed in 39 patients (36.8%), but the other 25 patients could not perform further resection for their tumors were closely neighbored to the important functional region or important tracts. Finally, in the whole cohort, the percentage of tumor resection volume was increased from (76.5±20.5)% to (94.2±8.7)%, with significant differences (U=2.000, P=0.000); 67 patients got complete removal, 25 sub-total removal and 14 partial removal; The total removal rate was significantly increased from 45.3% (48/106) to 63.2% (67/106): the average percentage of tumor resection volume in the second time of scan ([93.6±12.41%) was obviously increased as compared with that in the first scan ([86.3±20.21%, U=4.000, P=0.000). Conclusion High-field iMRI may increase the extent of glioma resection, and has significant impact on the intraoperative modification of the surgical strategy.