Abstract: The study of the geochemistry for typical Meso-Cenozoic volcanic rocks from northern Erlian basin shows that the main magmas are acidic to neutral. The relatively higher LREEs concentrations suggest that the volcanic rocks must be from surrounding continent block. The Jurassic volcanic rocks are belong to K-alkaline and came from shallow crust with weak repartition of magma. However, Tertiary volcanic rocks are calc alkaline series. The upwelling of asthenosphere and extension of overlying lithosphere in Jurassic controlled the fault basins and volcanic actions in this area, which had high extension degree in Jurassic. The abnormal geothermal gradient due to the strong volcanic activities offered the favorable conditions for the hydrocarbon-generation in the Erlian basin.