Exploring the differentiation characteristics of soil bacterial communities and their key influencing factors in the black soil region is of significant importance for understanding the ecological characteristics of microbial communities and for sustainable land management. This study adopted the ecological large-scale sampling method, taking the black soil area of Heilongjiang Province as the research object, a total of 180 typical dryland soil samples were collected from 36 sampling sites throughout the province, and through high-throughput sequencing technology combined with redundancy analysis, Mantel analysis, and multiple linear regression analysis, the differentiation characteristics and main influencing factors of soil bacterial communities in the black soil area were systematically revealed. The results showed that various chemical indicators, such as pH, available phosphorus, available nitrogen, total nitrogen, total potassium, and total phosphorus, had impacts on bacterial communities. Among them, pH was the main factor affecting the composition and diversity of bacterial communities in black soil regions. Proteobacteria, Verrucobacteria, Actinobacteria, and Patescibacteria in acidified soil (pH<6.5) were significantly higher than those in non-acidified soil (pH>6.5), while Acidobacteriota, Bacteroidota, Chloroflexi, Gemmatimonadota and Myxococcota in non acidified soil were significantly higher than those in acidified soil; alpha diversity of soil bacteria was significantly positively correlated with pH (P<0.05) for all samples, but the correlation was not significant for acidified soil samples (pH<6.5). When pH increased above 6.5, higher pH was more conducive to maintaining soil bacterial community diversity.