Abstract: Mantle peridotite xenoliths, including spinel peridotites and garnet peridotites, are found entrained in the Quaternary basalts in the Halaha river and Chaoer river area, the middle of Great Xing'an Range. This study focuses on the spinel peridotites, which could be divided into harzburgites and lherzolites. Most of the harzburgite xenoliths are characterized by generally higher equilibrium temperature (1072~1193℃), large variation in their mineral and chemical compositions, and high-forsterite olivine and high-Cr# spinel, which indicate they are the relics of aged lithospheric mantle. In contrast, the lherzolite xenoliths are relatively homogeneous in their mineral and chemical components, with wide range of calculated equilibrium temperature, which indicate they are modified lithospheric mantle, possibly reflecting that part of the lithospheric mantle has been modified by the interaction between asthenosphere and the lithosphere at different depth. It is deduced that the Xing’an-Mongolia orogen have a great amount of aged lithospheric mantle, which is distinguished from the intensively modified and destroyed lithospheric mantle beneath the eastern North China Craton.