Recombinant Anti-CEA x Anti-TNFα Bispecific Antibody (scFv-CH3) contains two chains. The anti-CEA scFv is fused to the Knob-CH3 domain via a hinge region and the same as the anti-TNFα scFv to the Hole-CH3 domain, or vice versa. The KIH CH3 domains can facilitate to form a heterodimer and this bivalent binding leads to improvement in avidity. This BsAb can retarget cytokine (TNFα) to tumor cells. It is designed for the research of Breast cancer; Ovary cancer; Colon cancer; Lung cancer therapy.