Abstract: The purpose of this experiment was to study the effects of feeding model on small intestinal microbial diversity of Tibetan pigs.Five healthy weaned Tibetan pigs with uniform body weight were selected in the experiment, and were grazed during the day and supplemented with a small amount of corn after grazing at night. Another five healthy weaned Tibetan pigs with uniform body weight were selected for house feeding, and were fed-corn soybean meal diet. The experimental Tibetan pigs were raised in two feeding methods until slaughter at the age of seven months.The contents of duodenum, jejunum and ileum of each test pig were collected after slaughter, 16 S rRNA gene sequences were amplified by PCR, sequenced by high-throughout sequencing technology, and the sequencing data were analyzed in terms of microbial operational taxonomic units（OTUs）, Alpha indexes（Chao1,Observed species, Shannon, Simpson, Faith′s PD and Pielou′s evenness index）, principal component analysis（PAC） and taxonomic levels analysis. The results were as follows: the sequenced sequences of 16 S rRNA genes were all between 1 400-1 500 bp in length. The number of OTUs in grazing Tibetan pigs and housed Tibetan pigs were different, the Alpha indexes of Chao1, Observed species, Shannon, Simpson, Faith′s PD and Pielou′s evenness in grazing Tibetan pigs were higher than those in housed Tibetan pigs, but there were no significant difference（P＞0.05）.There were differences in intestinal bacterial structure between grazing and housed Tibetan pigs.Proteobacteria, Firmicutes and Bacteroidtes were the dominant bacterial phyla in Tibetan pigs.The relative abundance of Proteobacteria in grazing Tibetan pigs was lower than that in housed Tibetan pigs, while Firmicutes and Bacteroidetes in grazing Tibetan pigs was higher than that in housed Tibetan pigs, but the difference was not significant（P＞0.05）. Burkholderiaceae, Comamonadaceae, Enterobacteriaceae, Prevotellaceae and Chitinophagaceae were the dominant bacterial families in Tibetan pigs, the relative abundance of Enterobacteriaceae and Clostridiaceae in grazing Tibetan pigs were significantly highter than housed Tibetan pigs（P＜0.05）.Ralstonia, Pelomonas, Escherichia, Prevotella, Selenomonas, Ochrobactrum, Bradyrhizobium, Clostridium, Lactobacillus and Campylobacter were the dominant bacterial genera in Tibetan pigs. The relative abundant of Escherichia and Clostridium in grazing Tibetan pigs were significantly higher than that in housed Tibetan pigs（P＜0.05）, while Campylobacter was significantly lower than that in housed Tibetan pigs（P＜0.05）. In addition, 48 bacterial species were identified in small intestine of Tibetan pigs, among which the relative abundance of Selenomonas bovis and Sharpea azabuensis in grazing Tibetan pigs was significantly lower than that in housed Tibetan pigs（P＜0.05）,while the relative abundance of Prevotella copri, Acidaminococcus fermentans, Streptococcus hyointestinalis and Lactobacillus mucosae in grazing Tibetan pigs was significantly higher than that in housed Tibetan pigs（P＜0.05）. This result indicated that the different feeding model could effect the structure of small intestinal microbial community of Tibetan pigs.