The newly—discovered Baixintan Ni—Cu deposit is located in the central part of the Jueluotage terran, in Eastern Tianshan area.The scale of the deposit has achieve medium-size. The research about the deposit may provide a new direction for the Ni—Cu deposit exploration. Based on the previous research, We make systematic research about the mineral compositon of olivine, pyroxene, plagioclase and chrome ,the whole rock Sr, Nd isotope.The Fo contents in Baixintan mafic—ultramafic rocks is range from 78.8 to 84.3. The contrasting Ni contents of olivine crystals is 299×10-6~2483×10-6. The En contents of orthopyroxene and clinopyroxene are respectively varied from 79.1~83.9 and 44.3~48.8. An content of plagioclase is from 60~83.9. The 100 Cr/(Cr+Al) is range from 51 to 73.9. In short ,the compositon of minerals in Baixintan intrusion vary with in a small range. Simulation calculations showed that the content of MgO and FeO of partental magma are 9.30% and 10.59% respectively. The Mg # of parental magma is 0.61, which is lower than the primitive, indicating the parental magma had experienced the process of fractional crystallization.The olivine begian to crysticallize alone from the parental magma at 1258℃. The total amount of olivine produced from the parental magma by fractional crystallization is ~7wt%. The sulfide segregation simultaneously with the olvine crystallize, and the mass ration between olivine crystal and sulfide melt is from 50:1 to 15:1. The orthopyroxene and clinopyroxene begin to crystallize at 1183℃ and 1143℃ respectively. The (87Sr/86Sr)i and εNd(t) rations are range from 0.70278~0.70439 and +4.51~+5.92 respectively.which reveals the magma source is depleted mantle, but more enrich than other typical Ni—Cu deposit in Eastern Tianshan. The Sr—Nd isotope trend indicate that the parental magma of the Baixintan deposit experienced 5%~20% crustal contamination. The olivine fractional crystallization and crustal contamination may played critical role in the formation of the Baixintan magmatic Ni—Cu deposit together.