Recombinant Anti-albumin x Anti-IL-6R Bispecific Antibody (scFv-CH3) contains two chains. The anti-albumin scFv is fused to the Knob-CH3 domain via a hinge region and the same as the anti-IL-6R 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 act as PK-modulated receptor antagonist. It is designed for the research of Lupus, rheumatoid arthritis therapy.