Recombinant Anti-DKK1 x Anti-SOST Bispecific Antibody (scFv-CH1/CL) is designed to be expressed as two chains. One scFv from an anti-DKK1 antibody variable domain is fused to CH1 and the other scFv from an anti-SOST antibody variable domain fused to CL, or vice versa. And the CH1 and CL domains are linked covalently via a natural disulfide bond. This BsAb can bind two factors simultaneously and promote osteoblastogenesis. It is designed for the research of Osteoporosis; Osteogenesis imperfecta (OI); Low bone mineral density; Fracture therapy.