As the special physiological characteristics and extremely complex micro-ecosystem of the intestine in piglets, to study the intestinal micro-ecosystem of piglets has become very important for production guidance. In this paper, advances in research on the ecology theory of intestinal micro-ecosystem in piglets, the composition and changes, the regulation factors, as well as the research methods and techniques of gut microbial flora are reviewed.［Chinese Journal of Animal Nutrition, 2010，22（5）:1181-1185］