Stutzerimonas kunmingensis 7850S is a piezotolerant bacterium isolated from the sediment of the Mariana trench. Here, we described the complete genome of strain 7850S, which contains a single circular chromosome of 4,775,870 base pairs with 62.66% G + C content, and harbors 4494 protein-coding genes, 65 transfer RNA genes, and 12 ribosomal RNA genes. The experimental results showed that strain 7850S could grow under hydrostatic pressure of 0.1–70 MPa. Genomic analyses led to identifications of numbers of high hydrostatic pressure-associated genes, such as the ones associated with unsaturated fatty acids, betaine, and ectoine. A complete set of denitrification genes and some heavy metal detoxification genes were also found in this strain. The presence of these genes suggests metabolic characteristics for adaption to hadal environments and provides insights to further understand adaption strategies and ecological roles of Stutzerimonas in hadal environments.