Grass carp reovirus (GCRV) seriously affects the grass carp farming, as the causative agent of grass carp hemorrhagic disease. In this study, we found the GCRV 096 NS38 protein contained one conservative PXXP motif similar to σNS of avian reovirus, with very low similarity rates with its homologous GCRV proteins of different genotypes. Furthermore, the soluble GCRV 096 NS38 protein was expressed in Escherichia coli, antiserum was raised and characterised. Addition of purified NS38 protein to culture media of Ctenopharyngodon idella kidney (CIK) cells clearly inhibited replication of GCRV 096 (genotype I); however, replication of GCRV GD108 (genotype Ш) was not significantly affected in CIK cells under the same conditions. It was not possible to induce cross-protection among GCRVs of different genotypes. GCRV multi-genotype should be considered and the NS38 protein was a promising candidate for developing therapies against grass carp hemorrhagic disease. Additionally, bioinformatics analysis suggested that the NS38 protein may be involved in viral genome replication.