On the basis of introducing the periodical achievement of 1:250 000 surveying project acrossing the border of northern Xinjiang, according to the geological facts and new progress that we got fiom 1:250 000 regional geological survey, and combining with the dates of territorial geologic investigation, we put forward a new theory to the gensis, tectonic setting of the Aermantai ophiolitic belt in the east Junggar area, Northern Xinjiang and the Mayileshan ophiolitic belt in the west Junggar area. We preliminary think that the Aermantai(Zhaheba) ophiolitic belt is a nappe structural belt(between the Ertix faulting belt and the Karamaili faulting belt) that is scooped tip by high-angle thrust nappe fault fi'om south to north during Variscan -lndonian Stage. We also think that the Mayileshan ophiolitic belt is a stratigraphic block (including ultrabasic rock, basalt, Pyroclastic rock and silicalite) that have the characteristics of quasi oceanic crust. It is Weakly Deformed and planar distributed. By the way, it does not have the properties of tectonic plate boundary, and may be it is the product of Epicontinental rift valley in southeastern Kazakhstan plate.