【Objective】 The black soil region of northeastern China is experiencing serious soil erosion problems. Although there are various types of soil erosion in this region, hydraulic erosion is still the most dominant form leading to soil degradation. However, current research efforts remain insufficient in examining how hydraulic erosion impacts soil microbial communities, particularly regarding the effects and mechanisms of single rainfall events on the soil microbial biodiversity and community structure. This study investigated how a single rainfall event influences the diversity and community structure of soil microorganisms and the mechanisms through which such alterations would occur. 【Method】 In this study, the experimental rolling hillslope cropland was selected in a typical black soil region of northeastern China for the field artificial rainfall experiments and field observations. In order to recognize the effects of the single rainfall event on soil microbial diversity and community structure in rolling hillslope cropland, three types of runoff plots were set up: bare land plots, soybean plots, and corn plots. The soil microbial diversity and community structure before and after the artificial rainfall event were examined through the application of bacterial 16S rRNA and fungal ITS third-generation high-throughput gene sequencing technology. Then the variations of soil microbial diversity and community structure were compared before and after the artificial rainfall event. Moreover, the microbial populations that were most sensitive to the single rainfall event were recognized and their influences on soil carbon and nitrogen cycling as well as soil nutrient storage were investigated. 【Result】 The rainfall event produced contrasting effects on microbial diversity across different types of runoff plots. In bare land runoff plots, the rainfall event triggered an increase in both soil bacterial and fungal Alpha diversity. However, in soybean runoff plots, bacterial Alpha diversity declined and fungal Alpha diversity exhibited an upward trend. In contrast, corn runoff plots experienced simultaneous reductions in both bacterial and fungal Alpha diversity. The single rainfall event demonstrated no statistically significant impacts on the dominant populations of soil bacteria and fungi across the three runoff plots. However, significant differences in the relative abundance of specific bacterial and fungal species were observed (P<0.05) and these sensitive映瑩档敲敢捩潡汬漠杰楯捰慵汬⁡慴湩摯敳渠癷楥牲潥渠浲敥湣瑯慧汮⁩敺晥晤攮挠瑁獭潮晧†獴潨楥氠⁢敡牣潴獥楲潩湡椠湳⁰牥潣汩汥楳測朠⁴桨楥氠汲獥汬潡灴敩⁶捥爠潡灢汵慮湤摡督楥琠桯⁦戠氼慩挾歃⁨獬潯楲汯⁦楬湥⁸湩漼爯瑩栾攠慳獩瑧敮物湦⁩䍣桡楮湴慬⹹ increased by 2.37% after the rainfall event in the bare land runoff plots, whereas the relative abundance of Thaumarchaeota significantly decreased by 3.22%, and the relative abundance of Actinobacteria significantly decreased by 3.39%. In soybean runoff plots, the relative abundance of Bacteroidetes significantly increased by 3.69% after the rainfall event, the relative abundance of Verrucomicrobia significantly increased by 1.85%, while the relative abundance of Actinobacteria significantly decreased by 2.22%. In corn runoff plots, the relative abundance of Planctomycetes significantly decreased by 1.71% after the rainfall event. Among the fungal species, the relative abundance of Sordariomycetes significantly increased by 7.28% after the rainfall event while the relative abundance of Leotiomycetes significantly decreased by 6.74% after the rainfall event in bare ground runoff plots. Also, the relative abundance of Sordariomycetes in soybean runoff plots significantly increased by 7.08% after the rainfall event while the relative abundance of Tremellomycetes significantly decreased by 4.06%. In the corn runoff plots, the relative abundance of Dothideomycetes significantly increased by 7.35% after the rainfall event while the relative abundance of Mortierellomycetes significantly decreased by 3.11%. 【Conclusion】 This study revealed that single rainfall events have significant effects on the alpha diversity of soil bacteria and fungi in all three types of runoff plots at different magnitudes. Furthermore, the single rainfall event significantly impacted the relative abundance of specific bacterial and fungal dominant species with statistically significant differences before and after the single rainfall event (P<0.05). These results provide important data and a theoretical basis for precise regulation o�������������������������������������������������������������������������������������������������������������������������������