ABSTRACT The microbial community structures, sulfur speciation, and their correlations in soil samples in and around Xiangtan Liejiaqiao Coal Gangue Dump in Hunan province south of China were analyzed with gene sequencing, sulfur K-edge X-ray absorption near edge structure spectroscopy (XANES), and principal components analysis (PCA). The gene sequencing results showed that the microbes in soil samples fell into six phyla, i.e., Nitrospira, Actinobacteria, Firmicutes, Proteobacteria, Deferribacteres, and Ktedonobacteria. The dominant bacteria species in the four samples were Moorella glycerini, Escherichia coli, Leptospirillum ferriphilum, Ferrimicrobium acidiphilum, Sulfobacillus benefaciens, and Desulfomonile tiedjei. According to the XANES results, sulfur speciation in soil samples was composed of sulfate, sulfite, thiosulfate, and organic sulfur. The PCA analysis among physicochemical characteristics, sulfur speciation, and distributions of microbes showed that oxidation-reduction potential (ORP) was correlated to the bacterial population of Proteobacteria, while pH was correlated to Ktedonobacteria. Furthermore, the correlation between sulfur speciation (sulfate and thiosulfate) and microbes (Deferribacteres, Nitrospira, and Actinobacteria) was particularly significant. Sulfite and glutathione also presented a strong correlation with Ktedonobacteria and Proteobacteria.