Abstract: The study area is located to the north of Baicheng in the South Tianshan Mountains on the northern margin of the Tarim Basin in Xinjiang，and the research degree of alkaline rocks in the area is rel⁃ atively low. Through the petrological and geochemical research of the alkaline rocks in the area，the petro⁃ genesis and tectonic environment are explored. The study of major and trace elements shows that alkaline rocks are rich in alkali，high in potassium and aluminum，rich in Rb，Th，U，Pb and LREE，low in calci⁃ um and magnesium，and depleted in Sr，Ba，Ta，Nb，Zr，Ti，P and strong negative Eu anomalies. They belong to quasi-aluminous high-potassium calc-alkaline-potassium basaltic granites，and have the charac⁃ teristics of type I granites，which may be formed in the late orogenic-cocollisional tectonic environment.

Key words: alkali granites, geochemical characteristics, petrogenesis, tectonic significance