In this paper, through petrography analyses and geochemical researches of the later Paleozoic ultramafic rock, which is schriesheimite firstly recognized in the west of Dong Ujimqi, have been studied for their mantle nature and tectonic implications. In these rocks, main rock forming minerals are olivine, hornblende, orthopyroxene, and slight plagioclase and clinopyroxene. Geochemical researches indicate that the schriesheimites, which belong to ferruginous ultramafic rock and tholeiitic series, have SiO2(42.84%～43.96%), MgO(24.10%～26.10%), Na2O+K2O(1.52%～2.32%, ＜3.5%), and are higher in FeOT(12.67%～14.33%), Mg#(76.42～79.20) and low in m/f(3.03～3.54). These rocks have high REE (39.57×106～83.32×10-6) , slightly Eu anomalies (δEu＝0.90～0.95), enrichment in LREE and relatively depletion in HREE[(La/Yb)N＝4.04～7.66], with the high La/Nb(2.60～3.63), Ba/Nb(43.11～72.52) and Zr/Y(5.45～7.83), and low Th/U(2.54～3.03) and Nb/U(3.40～12.85) which similar to intraplate rocks from mantle magmatism. The rocks are enriched in LILE (Cs、Rb、Ba、Sr、K), and depleted in HFSE (Nb, Ta), which has clearly differences from the strong depleted of Nb and Ta of the island arc magmatic rocks. These rocks also have high compatible elements, such as Cr(769×106～2480×10-6) and Ni(454×106～901×10-6), which are higher than proto-magma. Thus, we consider that the schriesheimites, in the west of Dong Ujimqi, had been formed in extensional tectonics from partial melting of the Sp-peridotite, which was modified by the subducted slab-derived fluid. The extensional tectonics caused by within-plate anorogenic magamatism after the closure of Paleoasian Ocean. This report on the schriesheimites indicates the existence of the Early Permian ultramafic magmatism and anorogenic magamatism.