Abstract: The research of purity in diamond has been focused on B & N atoms for a long time. But the research of hydrogen in diamond is just begun rec ently. With the help of vibration spectra including infra-red & Raman spectra, we studied some natural diamonds from Hunan Province and Australia. The hydroge n is bonded in diamond. The first kind of bonded hydrogen is C-H. Where hydroge n can substitute for the carbon atom. Two sharp lines in the Infra-red spectrum at 1405cm-1 and 3107cm-1 are associated with the bending and str etching vibrations of the C-H bond； The second kind of bonded hydrogen is hydr ogen molecule (H2). A sharp line at 4156cm-1 (theoretical value) in Ram an spectrum and a sharp line at 4106cm-1 in Infra-red spectrum due to distorti on field are observed. The experimental value is lower than theoretical value be cause of the isotopic substitution possible (e.g. HD substitutes for H2). The molecular hydrogen is stable in the tetrahedral interstitial sites. But the most stable form of H2 in diamond is the association of a H atom at an anti-bond ing site with a bond-centered H atom；The third kind of bonded hydrogen is O-H &　H2O. There are two sharp lines at 3230cm［-1］ and 3814cm［-1 ］ in Raman spectrum. Owing to different surroundings, hydrogen would be bonde d to different atoms. Consequently, there could be different bonded hydrogen in diamond.