Objective To explore whether BzATP could promote the growth of primary cultured astrocytes (AS) of rat and its possible mechanism, and whether TGF-β1 was involved in the event. Methods The primary cultured AS were derived from new b Sprague-Dawley rats.Glial fibrillary acidic protein (GFAP) immunofluorescent stain was used to check the purity of cultured AS. Morphometry was used to detect the changes of AS. The proliferation index of AS was detected by BrdU incorporation assay. West blot was used to detect the changes of GFAP under different conditions. Changes of TGF-β1 gene transcription were detected by RT-PCR. ELISA was utilized to detect the variation of TGF-β1 protein in the supate. Results The purity of primary cultured AS reached to 99%. BzATP promoted the hypertrophy of AS including the elongation of AS processes and the enlargement of cell bodies, BzATP also promoted the expression of GFAP in existence of Ca2+, but had no effect on cell proliferation. BzATP increased the transcription of TGF-β1 mRNA and the release of TGF-β1 protein in existence of Ca2+. TGF-β1 neutralizing antibody partially inhibited the expression of GFAP induced by BzATP, but had no effect on AS proliferation and cell morphology. Conclusion BzATP enhanced the hypertrophy of primary cultured AS, increased the expression of GFAP partially through TGF-β1. Mechanisms of the enhancement of AS growth induced by BzATP other than TGF-51 pathway remains to be elucidated.