Abstract: 【Objective】 To clarify the characteristics of rumen microorganisms and the differences between goat breeds，so as to provide a reference for further study on relationship between growth performance and rumen microbial communities of different goat breeds.【Method】 Three healthy ewes of Du’ an goats and 3 healthy ewes of Nubian goats were randomly selected and slaughtered after normal feeding for 6 months.2 mL of rumen fluid was collected by filtering through 4 layers of gauze.Characteristics of rumen microbiota and the differences between breeds of Duan goats and Nubian goats were analyzed by 16S rDNA amplicome high-throughput sequencing technology.【Result】 Composition of rumen microorganisms of Du’ an goats and Nubian goats was similar at phylum level，with Firmicutes，Bacteroidetes and Proteobacteria as the dominant bacteria groups，and their relative abundance in the samples of Du’ an goats were 58.32%，29.41% and 4.26%，respectively，while their relative abundances in Nubian goat samples were 45.66%，38.69% and 6.59%，respectively.At the genera level，Quinella，Prevotella_1 and Rikenellaceae_RC9_gut_group were the dominant bacteria，and their relative abundance in Du’ an goat samples were 36.93%，9.67% and 12.07%，respectively，while their relative abundance in Nubian goat samples were 12.91%，13.92% and 11.47%，respectively.The results of analysis of different rumen strains among varieties showed that relative abundance of Uncultured_bacterium_k_bacteria（P<0.01，the same below）and Lentisphaerae（P<0.05，the same below）of Du’ an goats were significantly lower than that of Nubian goats at phylum level.At the genus level，the relative abundance of Quinella in Du’ an goat was significantly higher than that of Nubian goat；the relative abundance of Uncultured_k_bacteria was significantly lower than that of Nubian goats； but the relative abundance of Pyramidobacter，Ruminococcaceae_UCG-010，Proable_genus_10，Uncultured_bacterium_f_p-251-o5，Uncultured_bacterium_f_vadinBE97，Uncultured_bacterium_o_Bacteroides，Ruminococcaceae_UCG-002，Flexilinea，Desulfovibrio，Butyrivibrio and Mogibacterium of Du’ an goats were significantly lower than that of Nubian goats.Microbial community function prediction of PICRUSt2 showed that there were significant differences in carbohydrate metabolism，other amino acid metabolisms and nervous system functions between the rumen microorganisms of Du’ an and Nubian goats.【Conclusion】The dominant microbial communities in the rumen of Du’ an goats and Nubian goats are similar，but there are some differences in the composition，diversity and function of the microbial communities，especially the abundance of microorganisms related to plant fiber degradation，which may play an important role in the strong adaptability of goats.