Monacolin K is one of the important secondary metabolites of Monascus sp. The influence of Monacolin K production for Monascus M1 on four kinds of fermentation substrate were studied.And the mRNA expression of Monacolin K biosynthesis gene cluster was measured by RT-qPCR. The result showed that the concentration of Monacolin K was the highest(8.49mg/L)cultured by buckwheat while the concentration of Monacolin K was 7.12,4.77,2.11mg/L cultured by brown rice, oats, and rice. And there was positive correlation between the expression genes related to MK and the MK production, except for MKB and MKC. The different kinds of culture medium could influence the secondary metabolites production by stimulating the gene clusters.