<p>Har Lake (HL) is in the northeastern basin of the Qinghai-Xizang Plateau (QTP), sits at an altitude of 4379&#xa0;m, and is classified as a soda lake within a wetland ecosystem. Evaluating the archaeal and bacterial communities in HL could offer valuable insights into the biogeochemical cycling within plateau wetland lakes. Consequently, high-throughput sequencing of 16S rRNA genes was conducted in this study to assess the composition of HL microbial communities and their association with environmental factors. The HL archaeal communities comprised 5 phyla, 5 classes, and 30 genera, while the bacterial communities comprised 28 phyla, 52 classes, and 542 genera. The dominant archaeal phylum was <i>Thaumarchaeota</i> (30.30–93.07% relative abundances), followed by <i>Woesearchaeota</i> (6.79–67.78%), while the most abundant genus was <i>Nitrososphaera</i> (30.30–93.07%). The distribution of <i>Nitrososphaera</i> was significantly correlated with TN, Mg²⁺, and Ca²⁺ concentrations. Bacterial communities predominantly comprised the <i>Proteobacteria</i> phylum (59.33–74.70%), followed by Bacteroidetes (13.92–19.19%) and <i>Firmicutes</i> (0.69–9.60%). Dominant bacterial genera included halophilic hydrocarbon-degrading bacteria like <i>Oleibacter</i> (1.90–18.69%), <i>Perlucidibaca</i> (5.19–17.46%), and <i>Thalassolituus</i> (0.80–11.98%). The results suggest <i>Nitrososphaera</i> and <i>Woesearchaeota</i> may be key taxa involved in carbon and nitrogen biogeochemical cycling within HL. Additionally, the high abundances of halophilic hydrocarbon-degrading bacteria suggests that potential contamination of HL may have occurred due to frequent animal and human activities. Overall, this study provides valuable insights into the archaeal and bacterial community structures in high-altitude soda lake wetlands and their interactions with their unique environments.</p>