Abstract: The major histocompatibility complex (MHC) of sheep has high polymorphism, and closely associates with sheep diseases resistance. MHC is a research hotspot around the world and has made great progress. This paper introduces the structure and function of sheep MHC, the research status at home and abroad about the sheep MHC polymorphism and related research between MHC and sheep disease -resistant breeding. The paper also introduces the prospects for the application of MHC on sheep resistance breeding, and provides theoretical basis for sheep disease-resistant breeding of the study in the future.