The Jikelikuole mafic—ultramafic rocks in Qiemo County, Xinjiang, is located on the north side of the central section of Late Paleozoic Karamilan arc, the southern active belt margin of the Tarim plate, intruded into the formation of marine clastic rocks, carbonate rocks and intermediate—acidic volcanic rocks, the Third Member of Carboniferous Mandelaqiapu Formation. The mafic—ultramafic rocks are dunite, lherzolite, wehrlite, plagioclase bearing olivine websterite, websterite, olivine—gabbro, leucogabbro. Geochemical and petrographic characteristics show that fractional crystallization dominates the magma evolution and formation of the rocks during early magmatism, and olivine and orthopyroxene are the fractional/cumulated phases; the mineral crystal order is: spinel/olivineorthopyroxene clinopyroxeneclinopyroxene + plagioclasebrown hornblende/biotite. Primary magma may come from the primitive mantle or the Mg high basaltic magma about moderate degree of partial melting. The magma is originated from the the spinel stability domain and belongs to the tholeiitic series, which has undergone little immiscible separation of metal sulfide.