The Beishan orogenic belt is one of the areas where mafic- ultramafic intrusions are concentrated in the southern margin of the Central Asian Orogenic Belt and has attracted widespread attention because of the reservoir of Permian Cu- Ni sulfide deposits. Previous studies have mostly focused on the Xinjiang Pobei in the western Beishan area. Recently, with gradual in- depth understanding of Permian mafic- ultramafic rocks in the Gansu Beishan area, the newly discovered mineralized rocks have a trend of extending eastward gradually. Here we selected two typical Cu- Ni sulfides mineralized Luotuoshan and Xinanshan intrusions in the Liuyuan area of the central- eastern part of Beishan for geochronological, petrographic and isotopic geochemical studies. The lithologies of the Luotuoshan and Xinanshan intrusions are composed mainly of peridotite, pyroxenite, olivine gabbro, troctolite and gabbro, among which sulfides predominantly appear in peridotite and pyroxenite. The zircons U- Pb concordant age of a gabbro from Luotuoshan intrusion is 282. 6 Ma, which is consistent with the formation ages of mineralized mafic- ultramafic intrusions in Pobei area. Chondrite- normalized REE and primitive mantle- normalized trace element patterns of parental magmas of Luotuoshan and Xinanshan intrusions show strong depletion of Nb- Ta and moderate depletion of Zr- Hf, which are similar to those of typical sulfides bearing intrusions in Pobei and Eastern Tianshan areas. The Luotuoshan rocks have both elevated εNd(t) (+0. 42~+6. 10) and εHf(t) values (+7. 9~+14. 1), which are also similar to mineralized intrusions in the Pobei area, indicating their similar depleted mantle sources. The relationship between olivine Fo values and Ni contents and Cu/Zr ratios of their parental magmas indicate that the magmas underwent sulfide segregation during the process of olivine crystallization. Mixing calculations of isotopes indicate that about their parental magmas underwent 5% to 15% of crustal contamination during magma ascent and emplacement process, which may be the major reason for triggering sulfur saturation in magmas. The same diagenetic and metallogenic ages, similar geochemical characteristics of rocks and parental magmas, and similar sulfide saturation mechanism suggest that Permian mafic- ultramafic intrusions in the Gansu Beishan area probably have similar metallogenic potential to those in Pobei area, which provides important information for further prospecting of Cu- Ni sulfides deposits in the central- eastern part of the Beishan orogenic belt.