Recombinant Anti-CA125 x Anti-HER2 Bispecific Antibody (IgG-Fv) is formed by an Immunoglobulin G (IgG) and a fragment variable Fv region, in which the Fc of IgG is engineered by KIH. The Fv region of an anti-CA125 antibody variable domain is fused to the C terminal of an IgG of anti-HER2 antibody, or vice versa. The format retains desired characteristics of intact antibodies. This BsAb can bind two factors simultaneously. It is designed for the research of Breast cancer; Gastric cancer; Prostate cacncer; Ovarian cancer; Solid tumors therapy.