Germ-free (GF) pigs are a special and adaptable experimental animal model for biomedical studies and animal productions, which are negative for bacteria, viruses, yeast and fungi tested by current microbiological examination. GF pigs were initially used in cleanse of epidemic diseases in animal production and in a bid to study the relationship between animal disease and intestinal flora. Because of the similarities to humans in anatomy, physiology and hematology, and the clear microbiological background, GF pigs have been playing an important role in detecting the relationship between intestinal flora with growth and the development of diseases in medical biology, and also providing a special medical animal model for intestinal flora targeted prevention, diagnosis and treatment for update technology research in the clinic. This paper reviews the characteristics, advancements and research tendency of GF piglets.