Detailed knowledge of airflow characteristics in nasal cavities is essential to understanding of the physiological and pathological aspects of nasal breathing. My research team have developed an exact technique for 3D computational anatomic model with the high resolution CT data that use Mimics software(an medical imaging software and Rapidform(an applied CAD software). In this article, the airflow inside the nasal cavity, after the transnasal endoscopic surgery of anterocentral skull base, was investigated numerically and experimentally. In order to remove the brain tumor where it locates in the anterocentral skull base, doctors may have surgery through the nasal cavity using the endoscope, by removing and upper part of the nasal septum, rather than by opening the cranium. This operation method shows a tendency to increase because of the surgery accuracy caused by a clear view from endoscopy, shortened operation hours, and lower riskiness compared to cranioclasty. However, there is a possibility that functions of the nose may decreases. We established the procedure for creating the anatomically correct nasal cavity model from CT data, using the medical imaging software(Mimics 16.0) and the applied CAD software(Rapidform XOS3). Numerical and experimental models of pre- and post-surgery nasal cavity were created by the aforementioned procedure under the ENT doctor’s advice. The numerical results by using ANSYS/Fluent were compared with the PIV experimental results.