Thanks to the microstructure, perfect antigen identification and bacteriophage selection, Nano-antibody exhibits high affinity, high specificity, strong penetrability, and prones to genetical modification and expression. With completely available sequence, Nano-antibody can be stably produced with high quality by recombinant expression in vitro, avoiding the inter-batch difference in traditional antibody production. With its unique physical and chemical stability, Nano-antibody, as a new research tool, promises to be used in antibody drug research, basic medical research, diagnosis and treatment of diseases such as cancer and infectious disease.