Recombinant Anti-albumin x Anti-IL-6R Bispecific Antibody (F(ab')2-scFv2) is designed to be expressed as two chains combined via a hinge region. The scFv of the anti-albumin specificity is fused to the C terminus of the anti-IL-6R Fab fragment, or vice versa. This format comprises four binding sites (two same scFv regions and two same Fab fragments), two for each antigen. This BsAb can act as PK-modulated receptor antagonist. It is designed for the research of Lupus, rheumatoid arthritis therapy.