Abstract: Yolk immunoglobulin (IgY),a polyclonal antibody,has garnered considerable attention for its role in conferring passive immunity against bacterial and viral diseases.This paper comprehensively reviews the current research on the fundamental structure and physicochemical properties of IgY.Additionally,the paper emphasize the diverse applications of IgY in preventing and treating bacterial and viral diseases,offering valuable insights for future research and the broader utilization of IgY in aquaculture.