Recombinant Anti-CD55 x Anti-CA9 Bispecific Antibody (scFv-IgG) is formed by an IgG and two scFv fragments. The scFvs from an anti-CD55 antibody variable domain are respectively connected to the N terminus of the anti-CA9 IgG heavy chains or light chains to form scFv-(H)IgG or scFv-(L)IgG. It is a type of appended IgGs and has 2+2 antigen-binding valency. This BsAb can recruit complements to tumor cells. It is designed for the research of Renal cell cancer (RCC); Solid tumors therapy.