Recombinant Anti-IL12 x Anti-IL18 Bispecific Antibody (scFv-CH3) contains two chains. The anti-IL12 scFv is fused to the Knob-CH3 domain via a hinge region and the same as the anti-IL18 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 and inactivate two ligands simultaneously. It is designed for the research of Arthritis therapy.