N 6-methyladenosine (m 6A) is a prevalent modification of RNA in eukaryotes and plays an important role in the process of mRNA translocation, stabilization and translation. m 6A exerts different influences on the viral replication cycle, and both viral replication and host immune response to the virus are affected by m 6A. In this review, we summarize recent studies on the mechanism of m 6A modification and its effects on viral replication and host immune response, in order to provide a reference for epigenetic regulation in the viral life cycle.