The bacterial diversity and community structure in rhizosphere soil of Betula platyphylla, a pioneer species in the succession of a natural secondary forest ecosystem, were studied using high-throughput sequencing technology. The results showed that bacteria from 28 phyla, 90 classes, 126 orders, 213 families, and 286 genera were detected in the rhizosphere soil samples. The relative abundances of the top 8 dominant bacterial phyla in all three sampling sites were greater than 1%; they were Proteobacteria, Acidobacteria, Actinobacteria, Gemmatimonadetes, Chloroflexi, Nitrospirae, Verrucomicrobia, and Bacteroidetes. The sum of the relative abundances of the first three phyla in each sampling site was above 60%. The analyses of the alpha diversity index, cluster heatmap at phylum level, and the PCoA of bacterial communities in rhizosphere soil of B. platyphylla showed that, among the three sampling sites, the species compositions of soil bacteria were similar in Xiaojinggou (B2) and Hadamen Forest Park (C2), which were different from Jingerliang (A2). The species diversity and abundance (ACE index) of Xiaojinggou and Hadamen Forest Park were significantly higher than those of Jingerliang, indicating there were significant differences in the ability of the bacteria to adapt to different environments. The RDA and correlation analysis of bacterial community structure with soil physical and chemical properties showed that the degree of influence of soil environmental factors was in the order of TN > pH > WC > AK > NN > AN > OM > EP. Of these, TN, pH, and WC were the main influencing factors for dominant bacteria in rhizosphere soil of B. platyphylla. The results of this study provide a theoretical basis for further understanding of the community structure and influencing factors of rhizosphere soil bacteria in forest ecosystems.