Recombinant Anti-FGFR1 x Anti-KLB Bispecific Antibody (F(ab')2-scFv2) is designed to be expressed as two chains combined via a hinge region. The scFv of the anti-FGFR1 specificity is fused to the C terminus of the anti-KLB 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 bind two factors simultaneously and act as mimetic hormone (FGF21) . It is designed for the research of Type 2 diabetes therapy.