Garnets and omphacites from three pieces of eclogites from the Dabie Mt. have been investigated by the Fourier transform infrared spectrometer (FTIR). All these minerals contain structural water which occur as hydroxyl (OH- ). The results demonstrate that nominally anhydrous minerals can bring water into the depth during deep crust subduction; the structural water in such minerals can be the part of metamorphic fluids; even in the ultra-high pressure stage, the metamorphic system is not "dry".