The triple monochromator is consisted of three image calibration monochromators by fine adjustments. The first two monochromators connected in subtractive dispersion mode to reduce stray light; the last two monochromators connected in additive dispersion mode to improve the resolution. The triple spectrometer is flexible for use in single, double and triple monochromator operation. Thanks to its tunable wavelength and adjustable notch, the triple spectrometer is mainly used for high-end Raman spectrum measurements, such as ultraviolet excitation Raman spectrum and low wavenumber Raman spectrum.