Bacterial colonization is a sign of bacterial infection in the hospital, and the bacterial colonization rate indicates the risk of bacteria infection. Newborn infection happen easily in the hospital. In recent years, sereral researches indicate that vaginal delivery, breastfeeding and probiotics usage and so on can lower the probability of intestinal pathogenic bacteria colonization, which can lower the probability of neonatal enterogenous infection. Therefore, there are many factors that can effect on newborn intestinal bacteria colonization, and because experimental conditions are limitated, so we have many problems to solove in the future.