Abstract: Objective To study the impact of different feeding patterns on feeding and intestinal flora in very low birth weight infants.Methods 60 preterm infants hospitalized were randomly divided into breast-feeding group and preterm-formula-feeding group.Stool specimens was sustained in three days after birth, 2 weeks and 4 weeks of age, respectively while feeding symptoms were recorded, real-time PCR technology was used to measure intestinal specimens Lactobacillus and Bifidobacterium.Results The incidence of feeding intolerance in breast-feeding group was 16. 7% (5 patients), and in formula-feeding group was 43. 3% (13patients), the difference was statistically significant (P< 0. 05). The number of intestinal lactobacilli and bifidobacteria at 2 weeks in breast-feeding group were (8. 62 ± 1. 35) cfu/g and (9. 10 ± 1. 33) cfu/g, and in formula-feeding group were (7. 32 ± 0. 80) cfu/g and (7. 62 ± 1. 22) cfu/g, the difference was statistically significant (P< 0. 05). The number of intestinal lactobacilli and bifidobacteria at 4 weeks of age in breast-feeding group were (9. 43 ± 0. 26) cfu/g and (9. 97 ± 0. 54) cfu/g, and in formula-feeding group was (8. 31 ± 0. 58) cfu/g and (8. 54 ± 0. 53) cfu/g, the difference was statistically significant (P< 0. 05).Conclusion Feeding mode is an important factor for feeding and intestinal microbiota in very low birth weight infants. The number of intestinal bifidobacteria and lactobacilli in breast-feeding group were higher than those in preterm-formula-feeding group, while the incidence of feeding intolerance was significantly lower in breast-feeding group.