Recombinant Anti-IL12 x Anti-IL18 Bispecific Antibody (Fab-Fv) is designed to be expressed as two polypeptide chains. The heavy chain Fd fragment and light chain of an anti-IL12 antibody are fused with the VL and VH domains of an anti-IL18 antibody respectively. It can form natural in vivo heterodimerization. This BsAb can bind and inactivate two ligands simultaneously. It is designed for the research of Arthritis therapy.