Abstract: The East Tianshan orogenic belt is an important Cu-Ni sulfide mineralization belt in China. However, the mantle source and sulfur saturation mechanism are still controversial. The newly discovered Yuyawan Cu-Ni sulfide deposit in the Dananhu arc provides a new target for these issues. The Yueyawan intrusion formed by two intrusive phases: the phase I is composed of gabbro, troctolite and olivine gabbro, and the phase II is composed of fine-grained olivine gabbro and fine-grained troctolite. The phase II rocks primarily contained sulfides. The rocks have low (⁸⁷Sr/⁸⁶Sr)_i (0.7033～0.70348), high εNd(t) (6.54～8.35) and low Pb isotopic ratios ((²⁰⁶Pb/²⁰⁴Pb)_i=17.828～18.014, (²⁰⁷Pb/²⁰⁴Pb)_i=15.446～15.478, (²⁰⁸Pb/²⁰⁴Pb)_i=37.495～37.698), indicating that the Yueyawan intrusion is not directly related to the Tarim Large Igneous Province, but originated from the depleted mantle and was replaced by subduction materials. The δ³⁴S of sulfide ranges from 0.03‰ to 4.09‰, which is consistent with the δ³⁴S of Carboniferous and Permian strata in Karatag area, indicating the addition of sulfur in the crust during the mineralization process. The mafic-ultramafic intrusions in the Dananhu arc have similar emplacement age and geochemical characteristics to those in Kangur shear belt and Middle Tianshan block, together with the denudation is relatively weak, which indicates that the Dananhu arc is an essential prospecting target for Cu-Ni mineralization in East Tianshan.