Fluorescence spectra of 5-sulfosalicylic acid （SSA） have been studied in dilute solution. SSA gives a fluorescence with a maximum emission wavelength at 401 nm and excitation wavelengths at 201

210

236 and 297 nm

respectively. There is an excellent linear relationship between fluorescence intensity and the concentration of SSA in the range of 2.5×10-7

8

.0×10-6 mol/L. At higher concentrations

fluorescence intensity of SSA in emission spectrum decreases gradually with the increase of concentration without deformations and position shifts. Furthermore the maximum excitation wavelength emerged red shift and split. This may be induced by self quenching of the formation of non-fluorescenced associated matter in higher concentration of SSA with exciting light.