Abstract: The formation and splitting of Gondwana land is still open to discussion.First,in this paper the Earth is considered to have involved the astronomical evolution and geological evolution.During the period of the astronomical evolution the Gondwana land formed at the south pole and high latitude areas.At the early stage of geological evolution the horizontal motion of magma might have driven the original crust to split and its northern edge might have drifted to where the outer-core liquid converged i.e.along the small circle from the Mediterranean Sea,southern edge of Qinghai-Tibet Plateau,Fiji,to the Caribbean Sea.On reaching low Latitudes,the splitted continents began to drift in the east-west direction and thus formed the mid-ocean ridges.