Abstract: The digestive tract of broilers is a dynamic ecological balance system composed of digestive tract mucosa, chyme and microorganisms. The microorganisms in the digestive tract can assist the body to digest and absorb nutrients, and are also an important protective barrier for broilers, which can maintain the health and promote the growth of broilers. At present, there are relatively few researches on broilers digestive tract microorganism. The composition and function rules of chicken digestive tract microorganisms in different parts of digestive tract, as well as the changes of microorganism community structure under age, diet, environment and other factors and their effects on body growth and development were reviewed by the author, aiming to lay a theoretical foundation for the study of poultry digestive tract microorganisms.