Abstract: In this paper, we divided the global mid-ocean ridge into internal and external ridge systems, according to the global distribution and kinematics characteristics of mid-ocean ridges and their structural and geometric relations with Pangaea at the period of their initial formation. The external ridge system, originated from the interior of Panthalassa and the Gondwana continent, starts at the Explorer Ridge, runs through the East Pacific Rise, the Southeast Indian Ridge, the Central Indian Ridge and the Gulf of Aden, and ends at the Red Sea. The internal ridge system, on the other hand, originated from the interior of the supercontinent Pangaea, extends from the Southwest Indian Ridge to the Mid-Atlantic Ridge, the Reykjanes Ridge, the Mohns Ridge, and ends at the Gakkel Ridge. The balance of global plate tectonics is achieved through the subduction-orogenic belt and diffuse plate boundaries between these two ridge systems to keep the spherical geometry of the Earth constant. The external ridge system has global tectonic significance. It is directly involved in the creation and development of the Pacific oceanic basin and  extinction of the ancient Pacific plate. In contrast, the internal ridge system caused continuous expansion of the Atlantic and Indian oceanic basins since the Mesozoic. Also since the Mesozoic, the external and internal ridge systems are collectively responsible for the lithosphere shortening in the subduction or orogenic belt of the western Pacific and northern Tethys by the ridge expansion.

Key words: mid-ocean ridge, global tectonic, plate movement, oceanic basin, plume generation zones, tectonic evolution