The mafic-ultramafic intrusions of the Hualong area in southern Qilian mountains is very important Ni-bearing rocks belt in Qinghai province. Ferruginous series mafic-ultramafic intrusions, high magmatic differentiation and high abundance of useful elements (Ni, Cu, Co), show that the Hualong rocks belt has good metallogenic conditions and prospecting potentiality. Geochemistry characteristics analysis and regional comparative study of Yulonggou,Yaqu,Xiashentang and Ashengong intrusions in this area, reveal that relative enriched LREE from spider diagram of chondrited REE and primitive mantle trace elements.And they had the characteristics of enriched large ionic lithophile elements(Sr, Rb, Ba) and relative depleted high field strength elements(Nb, Ta, Hf, Zr). The ratio of γOs is +80~+1183,together with ubiquitous depleted Nb and Ta,further explaining the close relationship with crustal contamination. Geochemical characteristics show that parent magma originated from mantle source metasomatic enriched once,and its εNd(t) ratio is -7.74～+8.36. The result suggests the magma source should had been located in asthenospheric mantle region that contaminated by mantle wedge material with subduction plate metasomatism. The riched silicon strata of Hualong rocks group created the condition of assimilation and contamination for sulfide immiscibility, finally caused the addition on the riched silicon material,occurred the sulfide immiscibility,and last formed the different grade magmatic Ni-Cu sulfide deposits in Hualong rocks belt, Qinghai province.