Objective To explore the anatomy of the sellar region and its adjacent structures so as to provide intimate morphological data for clinical image diagnosis and surgical operation. Methods Two Chinese adult male cadavers were examined along canthomeatal line with a 15T magnetic resonance(MR) imaging unit by using a spin echo sequence. After being embedded with 5% gelatin and frozen to -40℃ for a week, the specimens were sliced into 0.1mm continuous sections on transverse plane along canthomeatal line from down to up with SKC500 computerized freezing milling machine (milling accuracy of 0.001mm) in a -15℃ laboratory,the slices of the sellar region were as thin as 005mm, subsequently, the serial crosssections were photographed with high-resolution digital camera and imported into an animation computer. Typical slices were selected to investigate important structures with the corresponding MR images. Results Forty and forty-one T1 and T2 MR images, 304 and 310 thin sectional images were obtained separately. Comparing the MRI with thin sectional images, we investigated the sectional anatomy of the sellar region: 1. The internal carotid artery run sinuously in the cavernous sinus and formed some gaps with it. 2. The Ⅲ、Ⅳ、Ⅵ cranial nerves and trigeminal branches ophthalmic nerve, maxillary nerve displayed one by one from anterior to posterior in the lateral wall of cavernous sinus. In the section through the optic chiasm we could observe the stalk of hypophysis crossing the diaphragma sellae and connecting with the pituitary body which could seldom be shown in the thick sections. Conclusion Combination of slices obtained from computerized freezing milling technique and magnetic resonance images offers a better understanding of the complex anatomy structures and provid