Abstract: Tumor immunotherapy is currently the new direction for the treatment of cancer. Bispecific antibody can bind two different antigens, so the development prospect in the field of tumor treatment is very attractive. The most compelling trifunctional antibody and bispecific T-cell engager in bispecific antibodies have been marketed separately, with representative drugs as catumaxomab and blinatumomab, respectively. So far, nearly 100 antitumor bispecific antibody drugs are undergoing clinical trials and in-depth understanding of their mechanisms of action will provide more powerful solutions for cancer treatment. This review summarizes the progress of catumaxomab, blinatumomab and current highly promising bispecific antibody drugs, for the further development and application of tumor therapy.