Major and trace elements and the H2O contents of minerals in peridotite xenoliths hosted by the Cenozoic basalts of Bailin in the Cathaysia block were evaluated using electron microprobe, laser- ablation ICP- MS and Fourier transform infrared spectroscopy, respectively. The correlations among the major elements of the minerals define a melting trend with the degree of partial melting ranging from 0% to 21%. Most samples (21 out of 26) show depleted chondrite- normalized rare earth element patterns and a degree of partial melting <6%. The H2O contents (weight in 10 -6) of the clinopyroxenes, orthopyroxenes and olivines are 78×10 -6～262×10 -6, 37×10 -6～124×10 -6 and ~0, respectively. Although potential H- loss during xenolith ascent cannot be excluded for olivines, pyroxenes largely preserve the H2O content they have in the mantle prior to sampling by the host basalts, as inferred from ① the homogenous H2O content within single pyroxene grains, and ② the equilibrium H2O partitioning between the clinopyroxene and orthopyroxene. Based on the mineral modes and assuming a partition coefficient of 10 for H2O between the clinopyroxene and olivine, the calculated whole- rock H2O contents range from 15×10 -6～67×10 -6. The lack of good correlations of H2O contents with melting index, metasomatic index, redox state and temperature indicates that the controlling factors of H2O content in Bailin lithospheric mantle are complex. Compare with peridotite xenoliths from Jiande, the Bailin samples show comparable major and trace element compositions, but very heterogeneous H2O content. Therefore, the Cenozoic lithospheric mantle of the Cathaysia block represented by Bailin and Jiande is heterogeneous in the aspect of H2O content.