Gut microbial diversity provides insight into the basic function of a gut microbial ecosystem. In this study, restriction fragment length polymorphism 16S rRNA sequences was used to detect the intestinal microbial diversity of Hepialus gonggaensis larvae. The total DNA of microorganisms was extracted from the intestinal contents and 16S rRNA was amplified. A nearly full-length of 16S rRNA sequence library was constructed. The fingerprints of the microorganisms were analyzed by isolating plasmid and then digesting them with EcoRI, MspI, and HaeIII enzymes, respectively. The library established includes 35 restriction endonuclease types and a phylogenetic tree depicted the linkage of the isolated microbial from the guts of H. gonggaensis larvae. The dominant bacteria in the guts of H. gonggaensis larvae belong to Rahnella sp and Carnobacterium sp and accounted for 45.58% and 30.88% of the total 16S rRNA clones library, respectively. The result showed that bacteria diversity in the guts of H. gonggaensis larvae had some differences from those isolated from normal environment.