Abstract: A group of viral vectors including: first viral vector, wherein first viral vector carries first nucleic acid molecule, and the first nucleic acid molecule encodes envelope protein; second viral vector, wherein second viral vector carries second nucleic acid molecule, the second nucleic acid molecule encodes fusion protein, the fusion protein includes single-chain antibody and C-terminal domain of envelope protein, the C-terminal domain of envelope protein includes transmembrane region and intracellular region of envelope protein, the C-terminus of single-chain antibody connects with N-terminus of C-terminal domain of envelope protein, the single-chain antibody targets a specific antigen; first nucleic acid molecule and second nucleic acid molecule are arranged to express envelope protein and fusion protein, and the envelope protein and the fusion protein are in non-fusion form.