Abstract: 【Objective】The objective of this study was to assess effects of sugarcane tops silage treated by different bacteria on rumen microbial diversity of Nubian goats, and provide reference for sugarcane tops silage application in goat breeding.【Method】A total of 72 Nubian goats whose average weights were 24.5 kg were selected and randomly divided into four groups according to different microbial treatments of sugarcane tops silage in the diet:control group(CK), treatment 1(T1), treatment 2(T2), treatment3(T3), two replicates in each group, nine replicates in each replicate.Goats in the CK group were fed total mixed ration(TMR) which used sugarcane tops silage.The T1 group was supplemented with sugarcane tops silage which added Lactobacillus plantarum, L.casei, L.fermentum and L.rhamnosus.The T2 group was supplemented with sugarcane tops silage which added Aspergillus niger, Bacillus subtilis and A.oryzae. The T3 group was supplemented with sugarcane tops silage which added B.subtilis and Pediococcus lactis. After feeding, the effects of different bacteria on rumen microbial diversity of Nubian goats were investigated based on Illumina high throughput sequencing technology.【Result】Final OUT number from rumen fluid in four treatment groups of Nubian goats was ranked as T3(1637) > T2(1603) > C(1576) > T1(1560);Chao1 index of four groups was ranked as T3> T2> T1> CK, but the difference was not significant(P> 0.05, the same below).Shannon index ranked as T3> T2> T1> CK, T3 was significantly higher than CK and T1(P< 0.05, the same below).Simpson index ranked as T1> CK> T2> T3, and there was no significant difference among them.At the phylum level, Bacteroidetes and Firmicutes were absolute dominant bacteria in Nubian goat tumor gastric fluid, the relative abundance of Bacteroidetes was 57.50%-65.40%, and that in T1 was the highest.The relative abundance of Firmicutes was 14.39%-24.38%, that in T3 was significantly higher than other groups.The relative abundance of Cyanobacteria was the highest in T3.At the genus level, Prevotella-1 was the absolute dominant bacteria, its relative abundance ranked as T3> T1> T2> CK, but there was no significant difference among them.The relative abundance of Bacteroidales RF16 group_norank, Prevotellaceae UCG-001 and Succiniclasticum in T3 were all significantly higher than other groups.【Conclusion】The sugarcance tops silage which adds B.subtilis and P.lactis has the best effect.It can improve the microbial diversity and abundance of rumen microorganisms in Nubian goat, and improve the ability of rumen in Nubian goat to degrade the crude fiber and non-fibrous carbohydrate.