Abstract: RNA interference (RNAi) is a process induced by double stranded RNA and regulates the corresponding gene expression and gene silencing at mRNA level. As a conserved mechanism, it functions in kinds of eukaryotes and participates into the development regulation, antivirus defense, genetic damage repair, gene expression regulation and other important processes of life. There are initiation step, effecter step and amplification step in RNAi pathway where Dicer, AGO, RdRP and other proteins function alone or together. Here, we reviewed the advance of RNAi mechanism and functions of the main proteins in RNAi．

Key words: RNAi, Dicer, Argonaute, RdRP