Recombinant Anti-CD7 x Anti-saporin 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-CD7 antibody variable domain is fused to the C terminal of an IgG of anti-saporin antibody, or vice versa. The format retains desired characteristics of intact antibodies. This BsAb can be used in pretargeting system and deliver immunotoxin to tumor cells. It is designed for the research of Multiple myeloma (MM); Hematologic malignancies therapy.