Recombinant Anti-pre S2 protein x Anti-S protein Bispecific Antibody (scFv-Fc-scFv) is designed to be expressed as one chain, then assembled to a homodimer of bivalent scFv fragments and the Fc region of IgG. The anti-pre S2 protein scFv is fused to the N-terminus of Fc via a hinge region while another anti-S protein scFv is linked to the C-terminus of Fc. This scFv-Fc-scFv format has 2+2 antigen-binding valency by employing different scFv fragments. This BsAb can bind two antigens simultaneously. It is designed for the research of HBV infection therapy.