Abstract: Xishenba mafic-ultramafic intrusion is located on the northern margin of the Yangtze Craton. It is a newly discovered magmatic Cu-Ni mineralized intrusion in Hannan, Shaanxi Province, with significant mineralization potential. The intrusion consists of lherzolite, olivine lherzolite, and gabbro. The ore bodies are predominantly hosted within the lherzolite unit, with sulfides mainly comprising pyrrhotite, pentlandite, and chalcopyrite. Zircon U-Pb concordant age of the Xishenba intrusion is （854±3）Ma, indicating that it was formed in the middle Neoproterozoic. Geochemically, gabbro exhibit right-inclined REE patterns characterized by light rare earth element (LREE) enrichment and heavy rare earth element (HREE) depletion. In contrast, olivine lherzolite and lherzolite display relatively flat REE patterns with slight LREE enrichment. All samples are enriched in large ion lithophile elements (Rb, K) and depleted in high field strength elements (Nb-Ta, Zr-Hf).These geochemical characteristics are similar to those of other Neoproterozoic mafic–ultramafic intrusions along the northern margin of the Yangtze Block and global island arc basalts, suggesting a plate convergence setting. Olivine crystals from the ore-bearing lherzolite have Fo value of 76.0～80.9 mol%, Ni content of <200×10⁻⁶ to 1445×10⁻⁶. The correlation between these parameters suggests that sulfide segregation occurred in the parental magma of the Xishenba intrusion. Zircon from the lherzolite yield ε_Hf(t) value of −6.82～4.84, indicative of a depleted mantle source. Modeling based on Hf isotopes and Th/Yb–Nb/Yb systematics suggests that the magma experienced 10%~30% crustal contamination during ascent, which was likely the key factor triggering sulfide segregation. Comparative analysis with magmatic deposits formed in convergent settings, such as those at Xiarihamu, Kalatongke, and Sibao, reveals that the Xishenba Cu–Ni deposit possesses significant mineralization potential. Consequently, similar types of mafic-ultramafic intrusions along the northern margin of the Yangtze Block should be prioritized as targets for future Cu–Ni exploration.