Plateau mountains are one of the most sensitively fragile ecosystem to global climate change. Studying the characteristics of plateau mountain soil bacterial communities along the elevational gradient is of great scientific significance for revealing the structure and function of mountain microbial communities affected by global change. In this study, the characteristics and driving factors of soil bacterial community composition and diversity along the elevational gradient on the Mount Gangbala were analyzed based on the fine quadratic scale by using Illumina MiSeq high-throughput sequencing technology. The results showed that the soil bacteria of Mount Gangbala contained a total of 36 phyla, 125 classes, 307 orders, 477 families, 838 genera, and 1878 species. The 12 elevation belts were divided into 3 groups of low, middle and high (low altitude 3800-4100 m, middle altitude 4200-4500 m, high altitude 4600-4900 m). The total Operational Taxonomic Unit (OTU) number at middle altitude was the largest, but the number of unique OTU at middle altitude was the least. The richness of soil bacterial communities showed a unimodal trend with the increase of altitude, but the specificity of soil bacterial communities showed a U-shaped distribution pattern with the increase of altitude. The dominant phyla of the soil bacterial community in the Mount Gangbala are Actinobacteriota, Proteobacteria, Acidobacteriota, Chloroflexi, Verrucomicrobiota, Gemmatimonadota, etc. The Shannon diversity index of soil bacterial community gradually decreased with the increase of altitude, and was lowest at high altitude; while the Simpson diversity index was highest at high altitude, and the Chao index showed a unimodal trend with the increase of altitude. Principal co-ordinate analysis (PCoA) showed that there were significant differences in soil bacterial community structure along the altitude gradient, and there were also significant differences within the low-altitude soil bacterial community group. The redundancy analysis (RDA) showed that altitude, pH, total nitrogen, total phosphorus, and organic carbon had significant effects on soil bacterial community structure. Correlation analysis with environmental factors showed that altitude, pH, total nitrogen, total phosphorus, and organic carbon were significantly correlated with soil bacterial community structure. Mantel test showed that pH and altitude were the critical factors affecting soil bacterial community. Soil bacterial diversity on the Mount Gangbala showed a monotonous decreasing gradient along the elevation gradient, while pH was the key environmental factor affecting the characteristics of soil bacterial changes along the elevational gradient, and total nitrogen, total phosphorus and organic carbon were also important environmental factors affecting soil bacterial community.