Mineral material plays a very important role in wastewater treatment and sludge modification. Microbial metabolites are important components of the biological treatment system, and also play a very important role in improving the pollutants removal efficiency and methane production. In this study, the authors analyzed and characterized the soluble microbial products(SMP) and extracellular polymeric substances(EPS) produced from the graphite dosed anaerobic system. The results show that graphite exerts significant effects on the composition and content of the EPS and SMP, mainly due to the adsorption effect of graphite and its environmental toxicity. Fourier transform infrared spectrum(FTIR) analysis results show that adding graphite does not influence the types of the active group in SMP and EPS, but the relative content is changed. Three-dimensional fluorescence spectrum analysis results show that the main fluorescent materials in the SMP are humus(coenzyme NADH) and tryptophan analogs, whereas the main fluorescent materials in EPS are humic acid and tryptophan analogs. Fluorescence spectrum analysis results also indicate that graphite could significantly reduce the tryptophan and humic acid analogs. Graphite decreases the relative hydrophobicity of the sludge and improves the surface free energy, which is beneficial to the formation of microbial aggregates.