Pituitary abscess is a rare disease with a high preoperative misdiagnosis rate. Magnetic resonance imaging is the primary method for confirming pituitary abscesses before surgery. We reported magnetic resonance imaging findings of four cases of pituitary abscess (three males and one female) aged from 33 to 72 years old. All four cases underwent transnasal sphenoid surgery and had a good prognosis. The findings on magnetic resonance imaging were analyzed. Three cases showed ring enhancement of the capsule wall. Four cases showed thickened pituitary stalk, with the diameter of the lower end larger than that of the upper end. The position of the pituitary stalk where it was inserted into the upper edge of the pituitary was located at the middle and posterior 1/3 junction of the upper edge of the pituitary two cases were with the enhancement of the dura mater at the bottom of the temporal lobe. Two cases were with the enhancement of the dura mater of the petroclival region, and one case was with the enhancement of the cavernous sinus. There are few articles concerning abnormal magnetic resonance imaging around the sellar region of pituitary abscess. The findings of the four cases in this article suggest that the pituitary abscess has characteristic abnormal magnetic resonance imaging of the sellar region and its surroundings.