Objective To investigate the significance and value of 3D Slicer software in assisting endoscopic transsphenoidal resection of sellar tumors.Methods A retrospective analysis was performed for the clinical data of 60 patients with sellar tumors who underwent endoscopic transsphenoidal surgery in Yuebei People’s Hospital from July 2018 to July 2021， and according to whether 3D Slicer software was used for assistance， they were divided into observation group with 30 patients assisted by 3D software and control group with 30 patients receiving endoscopic transsphenoidal surgery alone. The two groups were compared in terms of time of operation， intraoperative blood loss， total tumor resection rate， improvement in visual field defect and hormone levels， and postoperative complications.Results All patients underwent the surgery safely， with no serious complications after surgery. The observation group had better outcomes than the control group in terms of intraoperative blood loss， time of operation， and the incidence rates of intercavernous sinus injury and cerebrospinal fluid leak （P <0.05）. Compared with the control group， the observation group had significantly better improvements in hormones and visual field defect after surgery （P <0.05）.Conclusions 3D Slicer-assisted endoscopic transsphenoidal resection of sellar tumors can achieve high-precision preoperative planning， which may help to shorten the time of operation and reduce the incidence rates of postoperative complications. ［Journal of International Neurology and Neurosurgery, 2022, 49(6): 29-34］