We constructed a eukaryotic expression plas-mid encoding Epstein-Barr virus latent membrane protein 2 (EBV, LMP2) and evaluated its effects on humoral immunity. First, the encoding sequence of the EBV LMP2 was amplified from B95-8 cell RNA by reverse transcrip-tion polymerase chain reaction (RT-PCR) and then was directionally cloned into eukaryotic expression vector pcDNA3.1. It was employed to evaluate immune response of the mice inoculated doubly with the DNA vaccine. The serum antibody against LMP2 was detected with enzyme-linked immunosorbent assay (ELISA). The recombinant plasmid pcDNA3.1-LMP2 was confirmed by the restrictive endonuclease analysis and sequence analysis. The serum titer of IgG antibody against LMP2 epitope in the mice immunized with the DNA vaccine encoding LMP2 was up to 1:4000. In conclusion, the EBV LMP2 DNA vaccine can induce a strong humoral immune response in mice.