Abstract: 【Objective】Bovine Viral Diarrhoea-Mucosal Disease Virus HB strain was a field strain isolated from a dairy cows flock in HeBei province . The study were progressed in order to realizing characters of HB strain, providing theory base for illuminating pathogeny, controlling infection and prevalence of BVDV;【Method】Genetic Variation on NS2-3 of Bovine viral diarrhea Virus HB-DCZ strain were amplified by RT-PCR. The product of PCR was cloned into pMD18-T vector, and then transfected into JM109. The recombinant plasmids were extracted and amplified by PCR and identificated by EcoRⅠand Hind Ⅲ enzyme digestion. The nucleotide sequence of the isolated virus NS2-3 was sequenced and amino acid sequence was inferred. Sequence analysis was performed with the aid of DNAstar softerware；【Results】The result showed that the obtained fragment was approximate 665bp by RT-PCR. There was no insertion in the isolated virus genome. EcoRⅠand Hind Ⅲ digestion of the recombinant plasmids resulted in two bands with sizes 702bp and 2635bp, indicating the specificity of the PCR. The cloned NS2-3 segment of HB-DCZ strain contains 665bp nucleotides and 208 amino acid. The homologies of nucleotide sequence of NS2-3 gene of HB-DCZ strain with other BVDV strains were 99.1%(184)，97.4% (ZM195), 92.3% (Osloss), 77% (OregonC24V ), 76.4% (NADL), respectively. The HB-DZC virus strain had no exogenous sequence insertion, gene recombination, gene rearrangement or gene deficiency. However, some nucleotide sequences were replaced. 【Conclusion】The HB-DZC was closed related to BVDV strains Osloss, 184, ZM195 nor the strains C24V, NADL; All the above results proved this virus was BVDV and which belongs to subtype Ib.