Recombinant Anti-TG x Anti-TPO Bispecific Antibody (scFv-CH3) contains two chains. The anti-TG scFv is fused to the Knob-CH3 domain via a hinge region and the same as the anti-TPO 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 and block the synthesis of thyroid hormones. It is designed for the research of Autoimmune thyroid disease therapy.