This study measured the area of the hippocampal structure using brain magnetic resonance imaging. We rebuilt a three-dimensional reconstruction of the brain and selected specific sections on the coronal plane, the cross section, and the sagittal plane and then measured the areas of the hippocampus using a software on the computer. In different sections, the left and right hippocampal areas were significantly different (P < 0.05), but the hippocampal areas of males and females are not concordant. There is no significant difference in the area in those aged 20 to 60 years. The hippocampal area is not correlated with the brain area in the same section. In conclusion, the standardization of the hippocampus is not suitable to judge the difference between males and females. The hippocampal area of healthy adults provides the criteria for atrophy of the hippocampus and a brief approach instead of the volumetric measures to apply in clinical diagnosis.