Abstract: The effects of estrogen on the expression of ER, NGF and ChAT in rats cerebellum were studied in this paper.The model of ovariectomized female rat was established to study the expression and distribution of estrogen receptor (ER), nerve growth factor (NGF) and choline acetyltransferase (ChAT) in the cerebellum after 17β-estradiol treatment by using technique of immunohistochemical ultrasensitive SP in Sprague.Dawley ratThe immunoreactive products were distributed in Purkinje′s cell, dentate nucleus, interstitial nucleus and fastigial nucleus of cerebellum, and the ER positive products mainly located in plasma, cytoplasmic membrane and neurite, also existed in nucleus.The general tendency of the expression of ER, NGF and ChAT positive products in cerebellar cortex and nuclei of ovariectomized rat is significantly decreased, while the intensity and quantity of the immunoreactive products ascended predominantly after 17β-estradiol treatment. The above results suggested that the estrogen upregulated the expression of NGF and ChAT. Furthermore, the similarity of their changing tendency implied that they were correlated and cooperated during the course in effect of estrogen on cerebellum. It also showed that the action of estrogen in cerebellum could via genomic and nongenomic mechanism.