The technique for generating color-coded speech spectrogram utilizing a white-light optical spectrum analyzer is described. First a conversion of the speech signal prerecorded on a magnetic tape to amplitude transmittance of photographic film is accomplished with a cathode ray tube (CRT) using density modulation method. The frequency pseudocolor-coded speech spectrogram is then obtained by means of a sampling narrow slit placed at Fourier plane in white-light optical spectrum analyzer. Operation of the system with theory of partially coherent ligkt is discussed briefly in this paper. And some color-coded Giiinese speech spectrograms are also provided.