MpSte12，the first homologous transcription factor （TF） of STE12 involved in regulating the growth and secondary metabolism in Monascus spp.，was identified via bioinformatics analysis to study the molecular mechanism of TF MpSte12 regulating the growth of Monascus spp. and the biosynthesis of Monascus pigments.The mpSte12 gene knockout strain ΔmpSte12 was constructed through homologous recombination.The differences in growth and metabolism between the wild-type （WT） strain Monascus ruber M7 （culture collection No.CCAM 070120） and the ΔmpSte12 strain were measured and compared.The results showed that the colony diameter of ΔmpSte12 significantly increased by 30.04%，and the number of mycelial branches increased by 33% compared with that of WT.The mycelial dry weight of ΔmpSte12 cultured in mCD medium at 28 ℃ for 7 days increased by 37.5%.The cleistothecial volume and ascospore yield of ΔmpSte12 were significantly reduced by 44.7% and 80% compared with that of WT.The conidial germination rate of ΔmpSte12 was significantly lower than that of the WT.The content of yellow，orange and red pigments in ΔmpSte12 increased by 127.72%，76.18% and 181.53%，respectively.It is indicated that MpSte12 is a key TF regulating the mycelial growth of Monascus spp. and the biosynthesis of Monascus pigments.