Abstract: In order to obtain the genome-wide cDNA of infectious bursal disease virus J1C7 strain and analyze its phylogenetic relationship. A proteinase K digestion and phenol-chloroform extraction method was used to extract dsRNA genome from IBDV J1C7 strain infected chicken embryo fibroblast (CEF). The specific primers were applied to amplify the two fragments of A and B segments by RT-PCR respectively. Then the fusion PCR was conducted to ligate the two fragments of A and B segments which possessed the overlapped sequences in order to construct the complete genome. The amplified PCR products were cloned by pMD-18T cloning vector. The results showed that the analysis of sequences identified that they were full-length segment A of 3260 bp (Genbank ID:EF646854) and segment B of 2827 bp (Genbank ID:EF646853) respectively. The amino acid alignment result indicates that IBDV J1C7 strain has the closest relationship with the attenuated IBDV strains (CEF94, P2, JD1, HZ2). The amino acid identity percent of VP5, VP2, VP4, VP3, VP1 were 99.3%, 99.3%-100%, 97.9%-99.2%, 96.4%-98.1%, 99.2%-99.9% respectively. The IBDV J1C7 strain belongs to the attenuated vaccine strains and the phylogenetic tree analysis indicates IBDV J1C7 strain is more closely related to the European and Chinese attenuated strains than those of vvIBDV and variant strains. This study laid the foundation for the construction of IBDV J1C7 strain ’s infectious cDNA. It also provided a reliable guarantee for further study of the relations between its structures and functions.