Abstract: The continental/lithospheric root formed at the bottom of the lithosphere is associated with depletion of the mantle plumes generated in the core-mantle boundary layer (CMB). It is mainly evidenced from three-dimensional seismic tomography and experimental and numerical simulations. The upwellings and downwellings represent, respectively, the high and numerical simulations. The upwellings and downwellings respectively, the high temperature/low velocity and the low temperature/high velocity zones. The long-wavelength mantle structure bears relations to tectonic features of the Earth’s surface. The boundary layers, either thermal (TBL) or chemical ones (CBL), will bring about direct of indirect effects on the global dynamic systems, and therefore, further study of the boundary layers on its structure, topography, thermodynamics, and physicochemical properties will be of crucial significance in solving those conflicting problems between the whole-mantle convection an the layered convection systems. Global seismic imaging and deep source seismic data have revealed that some formerly subducted fragments (slabs) seem to have continuously or intermittently sunk to the CMB and returned into the mantle plumes originated from the boundary. At present time, the most important task is how to establish an unified model between the whole-mantle convecting and the layered convection systems, rather than arguing whether the whole-mantle convection or the layered convection dominates independently the dynamic system. An integrated study, in terms of theoretical, experimental and numerical simulations on the whole-mantle convection system which is undoubtedly accompanied by the layered convection, locally small-scale of secondary convection during its spatial and temporal evolutionary history, consitues a main direction of today’s geodymamics.