Intestine and liver have very closely relationship due to the gut-liver axis,intestinal disease can affect the liver function,and the liver disease may also induce intestinal disorders.The germ-free animals have no living bacteria,fungi,viruses and parasites.The appearance of germ-free animals provides a powerful experimental tool for studying the interaction between the host and the intestinal microorganisms.At the same time,due to the characteristics of lacking normal intestinal flora,germ-free animals play a great role in promoting the study of gut-liver axis.In this paper,we will briefly review the application prospects of germ-free animals in the research of gut-liver axis.