Abstract: Exposure to the external aqueous environment enhances the susceptibility to infectious diseases in fish gills. To understand the mechanism of local innate immunity against infectious grass car preovirus (GCRV) in the gills, we identified the partial cDNA sequence of Mx, an antivira l effectormolecule, in rarem innowGobiocypris rarus. Realtime quantitative RTPCR (qRTPCR) was emp loyed to quantitate mRNA levels of apattern recognition receptor, Tolllike receptor 3(TLR3), and type Iinterferons indicatormolecu leMx. The artificia l infection experiments revealed tha tTLR3 andMx mRNA expressions were simultaneously significant upregulation at 1h postinjection (p0.05), and theMx mRNA expression kept at high transcription level tillmoribund (p<0.05). These results highlighted the importance of the gills as a tissue capable ofmounting a localimmune response, and the interferon pathway was activated to GCRV infection.