Objective To analyze the application value of MRI imaging examination in the endoscopic resection of pituitary adenoma. Methods 36 patients with pituitary adenoma who had definite surgical indications treated in our hospital from March 2012 to May 2015 were taken as the research objects. With the assist of MRI, transnasal transsphenoidal approach resection of pituitary adenoma was performed and MRI scan was continued during surgery to determine whether to expand the scope of tumor resection. For patients who had requirements for tumor resection, the surgery was ended. After expanding the scope of surgery in patients with residual, they were scanned by MRI. Repeated confirmation was performed until complete resection of the tumor. The protective effect of MRI assisted endoscopic surgery in pituitary function of patients with pituitary adenomas. Results In the 36 cases of patients with pituitary adenomas, there were 6 cases whose tumors were confined to the saddle. Postoperative MRI scan showed no tumor residual. The intraoperative scan of 30 cases of patients whose tumors were grown beside the saddle or on the saddle showed tumor residual which were removed furtherly. 7 cases were completely resected and 2 cases were incompletely resected. The total resection rate of pituitary adenoma in patients before extended resection was 75.00%. After extended resection, the total resection rate rearched 94.44% which was significantly higher than before extended resection (P<0.05). In 36 cases, 12 cases were completely remitted and 20 cases were partially remitted, 3 cases were stable and 1 case was in progress. The total remission rate was 88.89%. Conclusion To apply high-field intraoperative MRI system in resection of pituitary adenomas can improve the eradication rate of surgery, ensure the safety of surgery, objectively evaluate the surgical results in real time and differentially protect the anatomical structures around the hypophysis at the same time. It also can avoid surgical injury and reduce the risk of surgery.