As one of the youngest coastal wetland ecosystems in China, the Yellow River Delta has a gradual succession from bare land to grassland. Six typical communities were selected for the present study of the patterns and dynamics of soil microbial community under the gradual transitional succession. In which soil physicochemical properties such as soil pH, electrical conductivity, soil organic carbon, total nitrogen, and available phosphorus were measured simultaneously. The composition, structure, and variety of soil microorganisms were explored. Our results revealed that soil salinity decreased with succession, while soil organic carbon and total nitrogen exhibited an upward trend. Soil salinity, soil organic carbon, and total nitrogen were found to be the main factors that affect microbial composition and diversity in the Yellow River Delta. The phylum Gemmatimonadetes had the highest abundance in the saline bare land. Changes in the soil microbial composition and structure were observed under different succession stages, and microbial richness increased with succession. This research advances our understanding of the relationships among microbial species resources and soil environment with community succession in the Yellow River Delta. It could assist the identification of salt-tolerant microorganisms beneficial for future applications and saline-alkali land improvements.