Recombinant Anti-CD15 x Anti-CD64 Bispecific Antibody (Miniantibody) is a fusion protein of two scFv fragments combined with distinct specificity. One scFv of an anti-CD15 antibody variable domain is linked to another scFv of an anti-CD64 antibody variable domain by a flexible hinge region. This BsAb format has the decreased size and better penetration than conventional IgGs in the clinical diagnostics and potentially therapy. This BsAb can retarget neutrophils to tumor cells. It is designed for the research of Leukemia therapy.