[Objective] The aim of this research was to analyze the change of diversity and species abundance of bacterial communities in male Bactrocera dorsalis (Hendel) after 137Cs radiation treatment.[Methods] We used Illumina HiSeq high-throughput sequencing technology to sequence 6 intestinal samples of Bactrocera dorsalis.[Results] Proteobacteria (60.38%) and Firmicutes (24.33%) were the dominant phylum and subdominant phylum in the intestinal microflora of Bactrocera dorsalis respectively, and Enterobacteriaceae (60.38%) and Enterococcaceae (15.69%) were the dominant family and subdominant family. Moellerella, Morganella, Cosenzaea, unidentified-Streptococcaceae and Acidothermus have significant difference after irradiation.[Conclusion] Irradiation treatment significantly reduced the diversity and abundance of intestinal microflora in Bactrocera dorsalis. And we found significant differential species in different taxonomic level. This result provides a theoretical basis to improve the irradiated-induced damage to Bactrocera dorsalis.