The Kaipinggou peridotite is located in the western part of the northern Qaidam Basin. The peridotite experienced strong serpentinization, and therefore, it is difficult to determine its property and formation environment. Furthermore, the local enrichment of Ni in the peridotite with Ni=0.15%~0.23% indicates that metallogenic mechanism is rather complicated. A detail analysis was performed on chromite from the peridotite to understand the properties of the peridotite and the mechanism of nickel mineralization. Petrographic observation and electron microprobe analyses show that chromite is characterized by a distinct corerim structure with alumchromite at the core, and relatively high Al2O3, low FeOT, TiO2 and Cr#. These features indicate that the host rock formed in the subduction zone (SSZ). Alumchromite at the core is magmatic in origin. Calculation shows that it has an average crystallization temperature of 1372℃, an average crystallization pressure of 2.96 GPa and an average ΔlgfO2 of -1.42, indicating that it formed within the mantle asthenosphere. Highiron chromite around the rim is characterized by low Al2O3, high FeOT, TiO2 and Cr#, indicating that the rim of the chromite was affected by serpentinization alteration and Fe- rich fluids. In summary, it can be speculated that the protolith of the Kaipinggou peridotite was formed in the subduction zone, subsequently transformed into serpentine due to fluid metasomatism and modification, and finally uplifted to the surface.