Objective  To construct the eukaryotic expression plasmid pCAGGS-P7/NS2B of dengue virus serotype 2（DV2）NS2B and to prepare mouse anti-NS2B specific polyclonal antibody by immunizing mice with DNA.   Methods  An eukaryotic expression vector pCAGGS-P7/NS2B was constructed by PCR amplification of the NS2B gene fragment. Vero cells were transfected with lipid-mediated gene. The expression of target protein DV2 NS2B was detected in Vero cells. BALB/c mice were immunized with pCAGGS-NS2B to prepare anti-serum against NS2.   Results  The pCAGGS-P7/NS2B was constructed with a rather good immunogenicity. The antibody valence of anti-serum obtained from the immunized mice was 1∶3200. Western blotting and indirect immunofluorescence showed that the anti-serum could specifically recognize the DV2-NS2B protein.   Conclusion  Anti-serum against DV2-NS2 prepared by immunizing mice with DNA can specifically recognize the DV2-NS2B protein.