[Objective]The paper was to detect the species of endophytic bacteria in Chestnut (Castanea mollissima).[Method]The 16S rDNA-V4 region of endophytic bacteria in chestnut(sample name BL) was sequenced by Illumina Mi Seq high-throughput sequencing technology. The number of sequences and operational taxonomic units(OTUs) for each sample was sorted and calculated using Qiime and Mothur software. The abundance and α-diversity of species were analyzed.[Result]The number of effective sequences and OTUs were 21 167 /191. The rarefaction curves showed that adequate sampling was achieved,and the number of OTUs was close to saturation. The endophytic bacteria of chestnut belonged to 10 genera,including Koribacter(3. 48%),Solibacter(2. 59%),Bradyrhizobium(3. 57%), Rhodoplanes(7. 41%), Methylobacterium(4. 20%), Agrobacterium(19. 73%), Kaistobacter( 2. 05%), Sphingomonas(18. 66%),Acidovorax(35. 98%),and Methylibium(2. 32%). The dominant species were Acidovorax,Agrobacterium and Sphingomonas.[Conclusion]Illumina high-throughput sequencing technology provided more accurate and scientific data resources for the study of endophytic bacteria in chestnut. [Objective] The paper was to detect the species of endophytic bacteria in Chestnut (Castanea mollissima). [Method] The 16S rDNA-V4 region of endophytic bacteria in chestnut (sample name BL) was sequenced by Illumina Mi Seq high-throughput sequencing technology The number of sequences and operational taxonomic units (OTUs) for each sample was sorted and calculated using Qiime and Mothur software. The abundance and α-diversity of species were analyzed. [Result] The number of sequences and operational taxonomic units (OTUs) 21 167 / The endophytic bacteria of chestnut belonged to 10 genera, including Koribacter (3.48%), Solibacter (2.59%), Bradyrhizobium Rhodoplanes (7.41%), Methylobacterium (4.20%), Agrobacterium (19.73%), Kaistobacter (2.05%), Sphingomonas (18.66%), Acidovorax . 98%), and Methylibium (2.32%). The dominant species were Acidovorax, Agrobacterium and Sphingomonas. [Conclu sion] Illumina high-throughput sequencing technology provided more accurate and scientific data resources for the study of endophytic bacteria in chestnut.