Bispecific recombinant protein and application thereof

The invention discloses a bispecific recombinant protein. The bispecific recombinant protein comprises a high-affinity tumor targeting arm and a low-affinity fusion protein for blocking interaction of CD47 and SIRP alpha, and an antibody corresponding to the high-affinity tumor targeting arm does not bind CD47, the binding affinity of the antibody to a target antigen on a tumor cell is at least 6 times of the binding affinity of a monomeric fusion protein and a dimer corresponding to the fusion protein for blocking the interaction of the CD47 and the SIRP alpha on the CD47 on the tumor cell, and the fusion protein for blocking the interaction of the CD47 and the SIRP alpha comprises an extracellular truncation of the SIRP alpha. The invention also discloses a nucleic acid molecule for coding the recombinant protein and application of the recombinant protein and the nucleic acid molecule in preparation of medicines for treating tumors. The bispecific recombinant protein of the invention significantly increases