A bispecific antibody that is expressed as an anti-CD123 scFv fused with an anti-CD3 scFv, contains a His-tag at the C/N terminus for affinity purification. This BsAb can retarget T cells to tumor cells and is designed for the research of Acute myelogenous leukemia (AML); Chronic myelogenous leukemia (CML); Plasmacytoid leukemia therapy.