Phage display antibody library has been proven to be a powerful technique used in development of antibodies. Since it was established in 1990, the technology has made enormous improvement and played more and more important role in basic research of biology, immunology, oncology, protein engineering, ligand-receptor studies and proteomics among others in last two decades while there is no report about the application of it in aquaculture so far. It is a success implication of phage display technique in antibody engineering in which antibodies or antibody fragments are displayed on the surface of filamentous bacteriophage by genetic fusion to a coat protein of phage. Cooperating with the effective screening technique, affinity panning, these form the principle of phage display antibody library. The most characteristic of it is a direct physical link between phenotype and genotype. So, the technology makes it practicable to improve characteristic of selected antibodies by genetic manipulation. In the present work, the background, principle and advantages of the powerful tool over traditional hybridroma technolgy are summarized. In addition, several key problems possible to face in the course of application of the technology, including improving the diversity of library, augmentation of library size, generation of high affinity antibody and effective screening of specific antibody were dissertated. At last the possible implication prospect of phage display antibody technique in aquaculture was discussed, especially in elucidating the immune system of fish and producing large amount antibodies with important diagnostic and therapeutic value in fish diseases.