Extracellular polymeric substances (EPS) seem to play an important role in bioleaching. Generally, EPS consist of neutral sugars, lipids, a small amount of amino acid and some metabolites such as organic acid. In this paper, glucose, arginine, glucuronic acid and citric acid were used to study the effects of different components of EPS on the leaching of pyrite and indicate the facilitation of the direct contact between microbes and minerals on bioleaching. The iron contents of the experimental solution were measured in order to determine the dissolving rate of pyrite, and scanning electronic microscopy was employed to observe the changes of the surface characteristics of the pyrite. Some preliminary data obtained indicate that some kinds of components of EPS, such as glucuronic acid and citric acid, can promote the dissolution, while sugars and arginine suppress the decomposition, which may be attributed to their surface coating on the pyrite surfaces.