As a molecular fingerprint technique, Raman spectroscopy has been widely used in the qualitative identification and quantitative analysis for the targets, and it has also been gradually applied to the in situ detection of deep-sea extreme environment in past decades. The development of the laser Raman spectroscopy for deep ocean in situ detection is reviewed. The kinds of deep ocean Raman spectrometers developed by now are introduced, and the applications of the spectrometers for in situ detection of the seepage fluids, the sediment pore water, the carbonate minerals, and the hydrate are also presented. Finally, the factors that limit the broader application of the Raman spectroscopy in the deep ocean are summarized and discussed, which provides a reference for the future development of Raman spectroscopy.