Abstract: In North Xinjiang, there is an alkali granite zone extended in NW-SE direction along the southern bank of Ulungur River and parallel to the suture zone, i.e.Aermantai-Zhaheba Ophiolitic Melange Zone, between Junggar Plate and Altay Orogenic Belt. The Rb-Sr isochron ages of these granites are in range of 292-309Ma, showing that they are generated by the latest Hercynian magmatism after the syncollisional S-type and postcollisional uplift I-type granitoids in Altay region. The lkali granite are mineralogically characterized by the occurence of aegirine and arfvedsonite and chemically by high silicon and alkali, low calcium and magnesium, and enrichment of HFS elements, being typical A-type granites. The alkali granites were formed in the late stage of the Hercynian cafe-alkaline magmatism cycle in a very short period.They are in line with postorogenic A-type alkali granites, marking the end of the Hercynian Orogeny in Altay region and implying that the tectonic regime was changed from compression to extension.