According to the published gene sequence of the major surface antigen (P30), a pair of primers were designed and synthesized. At the 5' end of sense and anti-sense strand of the primers, EcoRI and BamHI sites were added, respectively. Using PCR, the coding sequences of P30 gene were amplified. The amplified gene fragments and plasmid pBV220 were digested with EcoRI and BamHI, and then ligated. The inserted gene fragment was sequenced by the chain termination method. The reading revealed that nucleotide sequence determined here was the same as the sequence published by Burg (1988), except one base was exchanged. The recombinant plasmid pBV220-P30 was constructed.