To develop a simple method for efficient expression of classical swine fever virus (CSFV) E2 protein. The pFastBac HT B vector (pFastHTB-M1) was modified by adding a melittin signal peptide sequence. The E2 gene fragment without the transmembrane region was cloned into pFastHTB-M1. The modified vector has clear advantage over the original one, as evidenced by the purified recombinant E2 protein that was detected significantly by SDS-PAGE. The modified vector has the potential for large-scale production and easy purification of the CSFV E2 protein or other proteins of interests.