The Hongqiling magmatic NiCu sulfide deposits are situated at the southern margin of the eastern section of the Xing’anMongolian Orogenic Belt. Over 30 mafic and ultramafic intrusions consisting mainly of peridotite, pyroxenite and gabbro crop out in the mining area. This paper analyzed the nature of parent magma, and PGE depletion and tectonic setting of these orebearing maficultramafic intrusions of the Hongqiling intrusions using geochemical study of major elements, trace elements and PGE. Analysis of major elements and trace elements shows that the Hongqiling intrusions are characterized by high MgO (2875%) and low TiO2 (044%), enrichment of light rare earth element (LREE) and depletion of high field strength elements (HFSE), as well as extremely low ΣPGE（averaging 208×10-9）and high Cu/Pd（averaging 2916×103）. These features suggest that they have the same magmatic source. Based on olivineliquid equilibrium and mass balance, the calculated compositions of the parental magma for the Hongqiling NiCu Sulfide deposit is a high Mg basaltic magma with MgO of 1074% and FeO of 778%, respectively. Immiscible separation of sulfides likely resulted in extremely loss of PGEs in the Hongqiling orebearing intrusions during early evolution of parental magma of the Hongqiling intrusions. Combined with the evolution history of the eastern segment of the Central Asian orogenic belt, it can be concluded that the Hongqiling intrusions formed in the late Triassic postcollisional extensional environment, with formation of the deposits affected by the slab breakoff after subduction of the Ancient Asian ocean.