The fluorescence spectra of melamine-water solution and milk powder-water solution mixed with melamine excited by UV-light were studied experimentally.The emission mechanism and the spectral characteristic were discussed,and the fluorescence spectra were analyzed and calculated by ordinate ratio transformation.The result shows that the melamine-water solution exhibits an obvious fluorescence peak nearby 350 nm and 370 nm with the optimal excitation wavelength of 240 nm.Compared with milk powder-water solution,the fluorescence peak location of milk powder-water solution mixed with melamine,excited by UV-light with same wavelength,changes from 328 nm to 350 nm.The other peak locations are basically changeless,and the relative fluorescence intensity of 370 nm is the maximum one.