Abstract: Coronal sections of the normal rat′s brain′s were observed by perfusion with a mixture of prepared Chinese ink and gelatin ,staining the blood vessels with 3-3′diamino benzidine (DAB) and benzidine dihydrochloride (BDHC) respectively.The microangioarchitecture of the thalamus, basal nucleiand internal capsule in rat was studied and its OD(optical density) was measured by the Leica microspectroscopy. Results showed that the capillary network from different neural structures anastomosed in to meshes of different forms and their densities varied differently.The capillary network ofthe thalamus was rich and complex.The capillary network ofthe caudate putamen and globus pallidus of the basal nuclei was similar and the meshes smaller. The capillary network oftheinternalcapsule was arranged in the same direction of the internal capsule′s peduncle ,their diameters were a little bit larger than others. The capillary network density of each nucleus was denser than that of the neurofibrillar areas.

Key words: thalam us, basal nuclei, internal capsule, microangioarchitecture, quantitative study