This study presents the comparison data of Os isotopic compositions of chromitites, chromitite bearing and free peridotites from Dongqiao and Luobusa ophiolites in Xizang(Tibet) and Sartohay chromitites in Xinjiang Autonomous Region with different ages. The results identify that chromitites and chromitite bearing peridotites show different Os isotope sources with chromitite free peridotites. The chromitite free peridotites (Zedang lherzolite) have a narrow range of n(187Os)/n(188Os) ratios from 0.1256±0.0008 to 0.1261±0.0008 consisting with Os isotopic compositions of Tibetan Tethys Ocean convecting upper mantle. But in contrast, the chromitites and the chromitite bearing peridotites yield a very wide range of n(187Os)/n(188Os) values as follows. The Os isotopic composition of the Palaeozoic Sartohay Al rich chromitites range from 0.1109 to 0.1256, corresponding Re depletion model ages (TRD) from 3.5 Ga to 0.6 Ga, the Cr rich chromitites from Mesozoic Tibetan ophiolites show the n(187Os)/n(188Os) ratios between 0.1175 and 0.1261 in the Dongqiao deposit with TRD = 1.5~0.1Ga, and n(187Os)/n(188Os) ratios of the Luobusa chromitites vary from 0.1038 to 0.1266, corresponding the TRD ranging mainly from Paleozoic to Archean. Their age distribution mirrors the tectonic history of the Tibetan Tethys Ocean and Paleo asian Ocean. These data suggest that part of these oceans is underlain by a fragment of ancient subcontinental lithospheric mantle (SCLM), left stranded in the oceanic lithosphere during the opening of these oceans. And in the supra subduction zone (SSZ) setting, the chromium, which is early partitioning into the bottom of mantle during the evolution of the Earth, removed again caused by high fO2 fluids or melts and enriched in the SSZ type ophiolite. Here we suggest that the recycling of the ancient SCLM plays a key role in the formation of the ophiolitic chromitites via the interaction of percolating melt with the ancient SCLM, and the ancient terrain surviving within the ophiolitic sutures likely becomes the diagnostic criterion.