Abstract: OBJECTIVE To investigate and analyze the risk factors for postoperative intracranial infection in endonasal transsphenoidal surgery for pituitary adenoma. METHODS The clinical data and surgical information of 543 patients who received endonasal transsphenoidal surgery for pituitary adenoma in our hospital from Jan. 2013 to Oct. 2017 were retrospectively analyzed. The related factors of postoperative intracranial infection in patients. RESULTS Of the 543 patients who received endonasal transsphenoidal surgery for pituitary adenoma, 23 patients had postoperative intracranial infections, with the infection rate of 4.23%. Totally 18 strains of pathogens were isolated from the patients, of which 10 (55.5%) strains were gram-positive bacteria, 7 strains (38.9%) were gram-negative bacteria, and 1 strain (5.6%) was fungus. The tumor diameter＞1cm, operation time and leakage of cerebrospinal fluid were risk factors for postoperative intracranial infections (P＜0.05). CONCLUSION Large tumor size, long operation time and leakage of cerebrospinal fluid were high risk factors of intracranial infections after endonasal transsphenoidal surgery for pituitary adenoma, and it is necessary to take targeted measures aiming at the influencing factors to reduce the postoperative infection.