Abstract: For the Datong basin Quaternary volcanic group can be subdivided into two parts:the northwestern area (i.e.the Datong volcanic group) and the southeastern area.The volcanoes in the northwestern area are typical of the central eruption with basaltic lavas of alkaline olivine basalts and ones in the southeastern area of fissure effusion with basaltic lava flow mainly consisting of olivine tholeiites.This paper studies difference between volcanic rocks in the two areas on the basis of petrology,geochemistry,rare earth elements,trace elements and their charactristics.