Abstract: Leaching processes and sulfur speciation on the surface of pyrite leached by the moderate thermophiles of Sulfobacillus thermosulfidooxidans were investigated by scanning electron microscopy,X-ray diffraction and sulfur K-edge X-ray absorption near edge structure spectroscopy.The results show that Sulfobacillus thermosulfidooxidans can significantly improve the leaching of pyrite and the leaching rate is up to 5.3 g·L^-1 after the process for 24 d.The surface of the mineral is obviously corrupted after leaching for 24 d with microbes and on the surface there are some visible crystalline floccules.Leaching products were found accumulating during the leaching process and the main composition is jarosite.The sulfur K-edge spectra indicates that the sulfur components are composed by pyrite and jarosite,whose mass fractions are 34.8% and 65.2%,respectively.