Objective To investigate the distribution of intestinal microflora in tree shrews with high-gradesarcomas and healthy tree shrews and compare their intestinal microbial structure and diversity, and to explore therelationship of intestinal microflora between high-grade sarcoma and healthy one in tree shrews. Methods Feces from threetree shrews with malignant high-level sarcomas were selected as the CA group, and feces from 6 healthy tree shrews wereused as the control group (NO). Bacterial diversity was identified using primers in the 16S V3+4 region. The intestinalmicrobial structure, abundance and diversity were obtained for both groups by cutting and filtering reads, clusteringoperational taxonomic units (OTUs), and analyzing the species annotation and abundance. Results The intestinalmicrobial structure of the tree shrews in the CA and NO groups were compared, and the Chao1 diversity, ACE and Shannonindices did not show significant differences ( P >0. 05). The NO group contained 640 OTUs, and 494 OTUs were found inthe CA group. At the phylum level, the abundance of Spirochaetes in the CA group was 0. 03%, which was significantlylower than that in the NO group (0. 12%; P <0. 05). The abundance of Firmicutes in the CA group was 77. 79%, whichwas higher than that in the NO group (47. 65%), but the difference was not statistically significant. The Bacteroidetesabundance in the CA group was 0. 75% lower than that in the NO group (8. 31%), but this difference was also notstatistically significant. Lactobacillus was a statistically significant biomarker in the CA group. Conclusions The structuralabundance and diversity of the intestinal microflora in tree shrews with high-grade sarcomas are lower than those in healthy tree shrews.