Abstract: North Altun ophiolite belt is an ophiolite melange zone located on the northern margin of the Altun Mountains. Rock associations of ultrabasic rock blocks, basic dyke swarms, gabbro rock blocks and basic lava composite the representative ophiolite suite located in Aksay of the East Altun Mountains. Geochemical studies of the Aksay ophiolite show that the ultrabasic serpentinite is high in MgO and poor in Al₂O₃, P₂O₅, CaO, K₂O, the chondrite-normalized REE patterns are relatively flat, and the ratio of sample to chondrite is close to 1. Basic lava rock is recognized by content of TiO₂, Al₂O₃, CaO, with the chondrite-normalized REE patterns being relatively right-inclined. Basic dyke swarms are recognized by content of TiO₂, Al₂O₃, with the features of Na₂O higher than K₂O, ∑ REE, and ∑ LREE/∑ HREE(2.22~4.45). Geochemical studies indicate that the Aksay ophiolite was formed in a Mid-Ocean Ridges (MOR) environment and was reformed by subsequent Suprs-Subduction Zone (SSZ). Geochronologic studies of zircon U-Pb show that the Aksay ophiolite was generated at 514.6±8.8Ma of Cambrian period.