Abstract: The extreme environment of the deep-sea hydrothermal zone makes the hydrothermal zone organisms form a unique survival mechanism, namely, the symbiotic and epiphytic relationship with microorganisms. In this study, the species and functions of symbiotic and epiphytic microorganisms from Gigantopelta aegis in the Longqi hydrothermal region of the southwest Indian Ocean were analyzed using high-throughput sequencing technology. Based on the sequencing results of V3-V4 region of 16S rRNA gene, it was found that 99.99% of the symbiotic and epiphytic microorganisms belonged to the bacterial domain, and the highest abundance was proteobacteria γ-, ε-, and α-proteobacteria. The symbiotic and epiphytic communities of Ga1 and Ga3 were dominated by γ-proteobacteria, while ε-proteobacteria dominated individual Ga2. The results showed that the symbiotic and epiphytic bacteria species of different individuals living in the same hydrothermal region existed a big difference. The results of metatranscriptomic sequencing were basically consistent with the results of amplicon sequencing, that is, proteobacteria had the highest relative abundance among the symbiotic bacteria, and high abundance of sulfur metabolism, hydrogen metabolism, methane metabolism and environmental stress response genes were found.at same time The study on the symbiotic and epiphytic microorganisms of Gigantopelta will help to explore the survival and adaptation strategies of deep-sea hydrothermal vents, and lay a foundation for further research.