Sodium dodecyl sulfate(SDS) is often used to reinforce the fluorescence of some materials,which need to know the fluorescence from SDS.A steady fluorescence spectrometer was used to analyze the SDS solution with different concentrations.The fluorescence spectra covers longer wavelength scope in ultraviolet light region.The position of the first fluorescence peak ranges from 290 nm to 300 nm with red shift with increase of concentration and fixes at 300 nm as reaching critical micelle concentration.Hereafter,bimodality appears at 300 nm and 330 nm.The first fluorescence peak should derive from the excited oxygen atom between carbon and sulfur.The excited oxygen atom,bonding with sulfur,should generate the peak at 330 nm is traversed.At the same time,fluorescence lifetime of various concentrations SDS.Fitting routine is applied to decay curve and calculates average fluorescence lifetime.The average fluorescence lifetime of SDS becomes long while concentration increasing,and the lifetime at 330 nm is longer than that at 300 nm.