Rare earth hydroxyl carbonate is an essential carbonate mineral form for rare earth elements in nature, and RE(CO3)OH is the main component of rare earth carbonate minerals and aqueous rare earth carbonate minerals. The mineral is present in nature. At the same time, carbonate minerals are the most important carrier minerals in the deep carbon cycle of the earth. As the main carbonate carrier minerals of rare earth elements, the stable structure of hexagonal RE(CO3)OH can provide a stable carrier for the migration of rare earth elements. At present, there are still many controversies on the way of the hydroxyl oxygen coordination and the exact occupation of hydrogen atoms, and the study of hydroxyl carbonate minerals is still in the primary stage. The effect of hydroxyl groups on the structure of carbonate minerals is still lacking. In this experiment, the hexagonal Sm(CO3)OH single crystal was synthesized by DS6×600t cubic-anvil-apparatus under the condition of 3 GPa and 800 ℃ with a particle size of 10～20 μm. The results of X-ray single crystal diffraction show that Sm(CO3)OH is hexagonal, with a=b=12.214 3(7) , c=9.839 3(6) , V=1 271.26(17) 3, and belongs to P6 space group. The structure shows that in the ab plane, the hexagonal network is formed by Sm3+ and ［OH］- connection, forming a basic repeating monolayer ２∞［(ＯＨ)Ｓｍ３／３］２＋. And ［CO3］2- connected these layers along c-axis, and the central Sm3+ is in the form of 9 coordination, connected with five carbonates,four monodentates are linked to a chelating junction, and the specific form of the coordination polyhedron is determined by connecting with three hydroxyl oxygen atoms. In this paper, the structure of the initial sample was further characterized by Infrared and Raman spectroscopy, especially OH- in the structure was analyzed in detail. The vibration modes and structure types of the inner groups were analyzed by the spectroscopic characteristics of the samples, especially the exact position and vibration characteristics of hydroxyl groups in the crystal structure. Infrared and Raman spectroscopy study indicated there were two different types of OH- in the structure of hexagonal Sm(CO3)OH. In both TF-IR and Raman spectra, band of 3 600~3 650 cm-1 was attributed to the hydroxyl groups polarized perpendicular to the (001) plane without hydrogen bonds and band of 3 450~3 500 cm-1 to the hydroxyl groups polarized in the (001) plane with hydrogen bonds,and the hydroxyl vibration of the reaction layer in the 3 369~3 380 cm-1 band and the 3 230~3 250 cm-1 band in the lower frequency band is the embodiment of the hydroxyl vibration with shorter O—H bond length. The H-D replacement experiment was verified by infrared absorption spectrum of deuterium sample. Because D atom replaced H atom, ρOH oscillating vibration and νOH stretching vibration absorption peak disappeared, O-D vibrational absorption peak appeared at 2 608.12 cm-1, indicating that deuterium generation was complete. The feasibility of deuterium generation experimental design was verified. As the hydroxyl groups which can change the characteristics of magmatic geodynamics, the properties at room temperature and atmospheric pressure and the physical properties of minerals provide important basic research value for geoscience problems.