Recombinant Anti-pre S2 protein x Anti-S protein Bispecific Antibody (scFv-CH3) contains two chains. The anti-pre S2 protein scFv is fused to the Knob-CH3 domain via a hinge region and the same as the anti-S protein scFv to the Hole-CH3 domain, or vice versa. The KIH CH3 domains can facilitate to form a heterodimer and this bivalent binding leads to improvement in avidity. This BsAb can bind two antigens simultaneously. It is designed for the research of HBV infection therapy.