Extracellular polymeric substance(EPS) seem to be important for bioleaching.For better control of the processes,the function of EPS of leaching bacteria is of crucial importance.Microcalorimetric measurement was used to study the three simulative components of EPS.The attachment of L-cysteine increases with its increasing concentration,which is Langmuir monomolecular layer adsorption.The attachment of glucose on pyrite is similar to mannose,which is not Langmuir monomolecular layer but multilayer adsorption.The results prove that the EPS mediates attachment and reacts with the sulphide surface and results in changed chemical properties of the mineral surface.It provides a new method to study the interaction between EPS and sulfide minerals.