Astrocyte has crucial roles in the central nervous system and accumulating evidence has shown its core function for brain complexity, plasticity and cognition. However, the essential key factors in the precise regulation of astrocytic differentiation remain largely uncharacterized. Here, we identified that RNF20, an E3 ligase of H2BK120 in the mammalian system, regulates astrocyte production from neural precursor cells. RNF20 deficiency by shRNA knockdown or deletion in conditional knockout mice impairs the astrocytic differentiation. Overexpression of RNF20 promotes astrocytic differentiation and can rescue the astrocyte production deficiency caused by RNF20 disruption. Furthermore, we demonstrate that RNF20 functions cooperatively with acetyltransferase MOF to promote astrocytic generation. RNF20-mediated H2Bub1 cooperating with MOF-mediated H4K16ac activates the transcription of Stat3. Together, these data indicate RNF20 is a critical regulator of astrocytic production, which may contribute to the understanding of neurological disorders with glial dysgenesis.