Objective To study the effect of normal aging on human hippocampus and entorhinal cortex with the comparative method of MRI and histology. Methods MRI-based area measurements through several special coronal levels(anterior commisure, mamillary body and lateral genicular nucleus) of the hippocampus and entorhinal cortex were measured; the using imaging analyzer, we counted neuronal density of the hippocampus and entorhinal cortex on the same coronal levels. Results The MRI-based area measurements indicated that in normal aging, there was no significant age-related atrophy in the hippocampus and entorhinal cortex. The result showed that the neuronal density kept constant during normal aging; while the MRI-based area measurements correlated with those after preparation. Conclusion In the hippocampus and entorhinal cortex, there was without no the decrease of the volumes or the loss of the neurons on special levels during normal aging. It was considered that the MRI-based area measurements of the hippocampus and entorhinal cortex might be of value for early diagnosis of some degenerative diseases of the CNS.