[Objective] In Escherichia coli, cytosine DNA methylation occurring at the inner cytosine in the sequence 5′CCWGG3′, is catalyzed by the DNA cytosine methyltransferase (Dcm) protein. Although dcm modification has been studied for nearly 37 years, the biological role for this gene is still unclear. In this study, we focus on the function of dcm in Streptomyces lividans. [Methods] dcm gene was isolated from E. coli and introduced into S. lividans 1326; HPLC-MS, methylation sensitivity assay and Southern blot are used to study the expression of dcm in S. lividans. [Results] the colony of dcm-containing exoconjugant is much smaller than wild type, and the production of actinorhodin in either MS agar plate or R5 liquid media was enhanced by two folds. [Conclusion] Epigenetic modification of the gonome of S. lividans by Dcm can activate the actinordin biosynthesis, providing an alternative way for genomic mining of cryptic bioactive metabolites.