Abstract: In the present paper,immunohistochemical and immunoelectronic microscopic methods was used to research the distribution of the β-END neuronal perikarya and fibers in the brains of 14 Tupaia belangeri,as well as its the localization of the organellae,the result showed that immunoreactive neuronal perikarya of the β-END in the diagonal band of Broca were first reported in this paper.The electronic microscopic observation showed that the positive products of immunoreactivity to β-END antiserum are located at the small pellets within the large granular vesicles and scattered on the rough surfaced endoplasmic reticulum.Immunoreactive neurons perikarya to β-END antiserum in the hypothalamus arcuate nucleus and its surrounding areas were visualized by light microscopy.Immunoreactive positive fibers and beaded varicosities to β-END antiserum were found in the periventricle areas,the paraventricle nucleus,the vicinity of the ependymal layer of the third ventricle and ependymal surface,mediobasal hypothalamus and its lateral areas,and in the internal and external layer of the median eminence.The release ways and its regulative factors of the β-END are discussed in the paper.