An analytical method of fast diagnosing organic matter in water is discussed. The concepts of total luminescence spectroscopy (TLS) and spectral fluorescent signature (SFS) technique are introduced. The total luminescence spectroscopy of water samples in combination with laser induced fluorescence (LIF) measurements using 532 nm wavelength excitation source are measured in the laboratory, and the spectral characteristics of dissolved organic matter (DOM) and chlorophyll a (Chl a) are analysed with spectral fluorescent signature technique. The curve of normalized fluorescence intensity against corresponding concentration of humic acid is showed. The possibilities of water quality monitoring in real time and on line based upon spectral fluorescent signature technique are discussed.