Histone modification as one of the key epigenetic regulation mechanisms plays critical roles in various biological processes, including regulation of chromatin structure dynamics and gene expression. Both histone methyltransferase and histone demethylases contribute to the establishment and maintenance of different histone methylation status. The 'effectors' which can recognize histone methylated sites build a relationship between these modifications and their down stream processes. This review summarized recent advances in histone methyltransferases and histone demethylases.