The Xuanwoling intrusion, located in the Beishan terrane, northeastern Tarim Block, NW China, is one of these mafic-ultramafic intrusions with cumulate texture and rhythmic layering. The Xuanwoling intrusion is composed of dunite, troctolite, olivine gabbros and gabbros, and the main minerals are olivine, pyroxene and plagioclase. Petrographical characters indicate that Xuanwoling intrusion had undergone fractional crystallization of olivine, spinel, plagioclase, and pyroxene in the magma evolution, and the crystallization sequence is olivine+spinel-> plagioclase -> pyroxene indicating the crystallization pressure is lower than 0.5~0.8GPa. Olivines from this intrusion have high Fo values (up to 90), which differs with Kalatongke, Huangshan and Jinchuan intrusions. Using Fo molecular of olivine to estimates the Mg# values of prarental magma of Xuanwoling intrusion is 0.73~0.75, and the crystallization temperature of the Xuanwoling intrusion is 1330~1350℃ higher than basalt liquidus temperature about 130℃. Therefore, the magma is a high temperature and high MgO of picritic magma, providing the new evidence for Permian mantle plume activity in northeastern Tarim.