Abstract: Infancy is key stage of gut microbiota colonization and establishment, infancy is also foundation for people to establish stable gut microbiota in adulthood. Composition of gut microbiota change is associated with pediatrics and long-term adult diseases. An infant's gut microbiota development is a dynamic process. There are many factors will affect an infant's gut microbiota development,including birth delivery formation, gestational age, feeding patterns, immune systems, family lifestyles, geographical location, usage of probiotics and antibiotics. In this paper, the influencing factors of gut microbiotain infants were discussed comprehensively.