The family Nodaviridae contains two genera, Alphanodaviruses and Betanodaviruses, which predominantly infect insects and fish, respectively. The genome of nodaviruse consists of two sin-gle-strand positive-sense RNAs (RNA1 and RNA2). RNA1 encodes protein A, catalytic subunit of RNA-dependent RNA polymerase (RdRp), and RNA2 encodes coat precursor protein which undergoes an autocatalytic mature cleavage into two viral capsid proteins β and γ. During the course of RNA rep-lication, a sub-genome RNA3 is synthesized which is not packaged into the virion from the 3’ termini of RNA1. RNA1 can self-replicate automatically absence of RNA2 and produce the sub-genome RNA3 persistently. The mechanism of RNA3 synthesis is the mechanism of premature termination. The paper also reviewed the regulation of RNA replication, the functions of non-structural proteins and the local-ization of RNA replication of the nodaviruses.