Recombinant Anti-albumin x Anti-IL-6R Bispecific Antibody (Fab-Fv) is designed to be expressed as two polypeptide chains. The heavy chain Fd fragment and light chain of an anti-albumin antibody are fused with the VL and VH domains of an anti-IL-6R antibody respectively. It can form natural in vivo heterodimerization. This BsAb can act as PK-modulated receptor antagonist. It is designed for the research of Lupus, rheumatoid arthritis therapy.