Abstract: The U-Pb zircon age of the meta-cumulus bojite in southern Bugt, Inner Mongolia is detected to be 2096±36 Ma. The result indicates that the rock was formed in Paleoproterozoic era. Study on the petrochemical and geochemical characteristics shows that it is the product in subduction environment, probably resulted from early volcanic arc magma activity during orogeny. It marks the beginning of a new tectonomagmatic cycle in the area. The rock may not be regarded as the result of the late Paleoproterozoic continental splitting.