A new design of hybrid plasmonic waveguide based on nanostructure has been proposed. Compared with the previous mixed plasmonic waveguides, the design make a vertical dielectric-slot configuration embed within the middle of the metal surface and the high-index dielectric structure. The closed structure can provide the ultra-compact mode confinement. The propagation loss due to the presence of the air slot can be greatly reduced. The design could improve the development of integrated photonic circuits.