Recombinant Anti-pre S2 protein x Anti-S protein Bispecific Antibody (Miniantibody) is a fusion protein of two scFv fragments combined with distinct specificity. One scFv of an anti-pre S2 protein antibody variable domain is linked to another scFv of an anti-S protein antibody variable domain by a flexible hinge region. This BsAb format has the decreased size and better penetration than conventional IgGs in the clinical diagnostics and potentially therapy. This BsAb can bind two antigens simultaneously. It is designed for the research of HBV infection therapy.