This is the 56th case since I changed from microscopic to endoscopic resection of large pituitary tumors through the nasal aperture in 2007, and until 2006, I had been resecting pituitary tumors through the nasal pterygoid sinus under the microscope, but I always felt that there were inconveniences: the operating instruments obstructed the field of vision; there were dead spots in the light; the anatomical structure was blurred, so the tumors that grew on the saddle of the sinus and had a tough texture could not be well resected. In 2006 and 2010, we went to Pittsburgh for the second time to observe the operation and concluded that the application of skull base microscope is not only limited to pituitary tumor resection, but also can be used for many operations alone.