Chemical compositions of gabbros from Shacun, Dabieshan and their feldspars are obtained by the wet method and EMPA respectively, and hydrogen speciation and structural water content of feldspars are investigated by FTIR. According to the chemical compositions, the 10 studied gabbros can be divided into two groups representing two different magmas. All analyzed feldspar grains contain structural water which occur as OH-, and the water contents (H_2O wt.) range from 135~658 ppm. Combining the results with the dataset of UHP ecologites from Dabieshan, the high H_2O character of the Shacun gabbros suggests that the subducted eclogites could be involved in the source. For both groups of gabbros, the water contents of the feldspars show negative correlation with the Mg# values of the whole rocks. It may be caused by the continual crystallization of amphiboles and/or magma degassing. The preservation of the correlation between water contents in feldspars and Mg# values of the whole rocks indicates that the initial water contents of feldspars have not been changed after crystallization, suggesting their validity of tracing magma evolution.