The invention discloses a high-efficiency automatic loading gear running-in device. The high-efficiency automatic loading gear running-in device comprises a fixing support, and the fixing support comprises at least one set of gear running-in unit. The gear running-in unit comprises a pinion shaft system and a gearwheel shaft system which are parallel to each other and are engaged with each other. A gearwheel of the gearwheel shaft system is provided with a gear loading device used for applying engagement force between the pinion shaft system and the gearwheel shaft system. The gear loading device comprises a gearwheel adapter block, a gearwheel shaft adapter block and a loading screw, wherein the gearwheel adapter block is fixed to the gearwheel of the gearwheel shaft system in the radial direction; the gearwheel shaft adapter block is fixed to a gearwheel shaft of the gearwheel shaft system in the radial direction and perpendicular to the gearwheel adapter block; the gearwheel shaft adapter block is further connected with an adapter block parallel to the gearwheel adapter block; and the loading screw is connected with the gearwheel adapter block and the adapter block.