Abstract: Phage display technology utilizes filamentous phage display proteins and polypeptides to extract a desired polypeptide or protein from a large number of variants. The antibody fragments screened and obtained by phage display library technology play an important role in disease diagnosis and treatment. This article briefly introduces the principles of phage display technology, summarizes the development of monoclonal antibodies, the development of antigenic microbial vaccines, and the application of peptide drugs. This review highlights the importance of phage display technology in the diagnosis and treatment of various human diseases such as cancer and autoimmune diseases etc.