Double GCRV outer capsid protein VP7 genes(0.9 kb)and β-actin promoter(0.56 kb)from Megalobrama amblycephala were amplified and cloned into gene transfer vector pFastBac^TM Dual to obtain recombinant pFastBac-β-VP7-1-VP7-2.Immune experiment and immunological effect were studied.The recombinant plasmids were divided into three groups based on doses:10,30,60 μg.30 μg pFastBac^TM Dual group and control group were designed in addition.Immune efficacy was determined by means of transcriptions of VP7,antibody detection by indirect agglutination reaction and challenge experiment on the 14th,21st,28th,and 49th days after immunization.The results showed that pFastBac-β-VP7-1-VP7-2 was transformed into body cell,VP7 gene could be controlled for expression constantly by β-actin promoter,and transcription of VP7 was still in process on the 49th day.Antibody was produced and the titers reached their peak on the 21th day after immunization.The mortality rates were 0%,0% and 5% respectively in 10 μg,30 μg and 60 μg vaccine immunization groups,30% in pFastBac^TM Dual group,and 100% in control group after GCRV injection.All results suggested that pFastBac-β-VP7-1-VP7-2 had good immuno-protective efficacy as DNA vaccine against GCRV.Therefore,the study provided important academic basis for research,development and application of the GCRV genetic vaccine.