Facial neural edema is the pathophysiological base of Bell's palsy. The middle cranial fossa approach is used to relieve the oppression of facial nerve at its most narrow course in the facial canal. In this research, the authors mainly discussed the internal auditory canal segment of facial nerve, completely in the shadow of the bony structure, which is inconvenient for transmastoid decompression. Therefore, the objective was to explore the definite position of the fundus meatus acustici interni from internal acoustic pore. Two hundred persons (age 22–60, 100 men and 100 women), presenting with healthy facial nerve, ear, and internal auditory canal, were investigated by computed tomography 3-dimensional reconstruction. Using statistical method to analyze, the authors obtained the definite position of the fundus meatus acustici interni, regarding the internal acoustic pore as the origin of coordinates. Our data provided more significant information for medical workers to improve the efficiency of operation and to prevent complications of surgery.