Abstract: Located in eastern Kunlun orogenic belt in Qinghai Province, the super-large Xiarihamu magmatic Ni-Cu sulfide deposit is the second ones after Jinchuan Ni-Cu sulfide deposit.Totally, 5 mafic-ultramafic intrusionswere developed 1n this mining area, in which some super-large economic ore-bodies have been found only in No.Ⅰintrusive rocks, but other 4 ones belong to basicto magnesium peridotite and eclogite, these maybe the results of at least two tectonic systems superimposed with magmatic activities. For the No.Ⅰintrusive rocks in the Xiarihamu deposit, their SiO₂ contentsvary from 34.11% to 54.28%, and m/f ratios range from 2.01 to 4.93, belonging to ferruginous basic-ultrabasic rocks.The Fo and Ni valuesof olivine show that the Xiarihamu Ni-Cu deposit had experienced multiple stage of magmatic mineralization, the positive and negative correlations between Fo value and Ni content from olivine stand for the immiscibility of sulfide in the early mineralization stage. Combined with regional chronology and other geological information, it's believed that the Xiarihamu super-large magmatic Ni-Cu sulfide deposit was the result of early lower Devonian magmatism and mineralization in the margin of Qaidam basin, eastern Kunlun orogenic belt. By the way, there maybe have better metallogenic conditions and prospecting potentiality in the depth of No.ⅠandⅡ intrusions, especially the place of magmatic origin or flowing direction, but the other three mafic-ultramafic intrusions that mainly belonged to magnesium peridotite have bad metallogenic condition on Ni-Cu sulfide deposit, and no economic value.