The three-dimension exaction and emission matrix fluorescence spectroscopy (3D EEM) was used to investigate the decomposition of DOM in environmental water treated by potassium ferrate. The results showed the changed regular of fluorescence of several organic maters during the treatment process

and the pH value performed an important role on the fluorescent intensity and position. The intensity of fluorescence experienced a quick-decay process and a slowdecay process. Such 3D EEM method can be used as a simple and quick method for the online monitor of variety fluoresce maters.