The typical mesophile Acidithiobacillus ferrooxidans was used to leach chalcopyrite. The characteristics of mineral surface, main components of mineral and the sulfur speciation on the mineral surface were investigated combining with SEM. XRD and sulfur K-edge XANES spectroscopy. SEM micrographs showed that the mineral surface was obviously corrupted and covered by some visible crystalline floccules after 24 days bioleaching. XRD analysis indicated that jarosite and chalcopyrite were the main components in the leaching residue. The sulfur K-edge XANES spectra indicated that the jarosite was the main component of the passivation layer and the chalcocite was the transient intermediate sulfur compound during the bioleaching of chalcopyrite. (C) 2011 Elsevier Ltd. All rights reserved.