The invention discloses a magnesium-smelting operation unit, belongs to the technology field of magnesium smelting reduction process operation equipment, and specifically relates to an operation unit dedicated for a magnesium-smelting vertical tank heat-storage reduction furnace. The invention provides a magnesium-smelting operation unit, which has a high mechanization degree and production efficiency and is capable of reducing work strength of workers and guaranteeing the product quality. The magnesium-smelting operation unit comprises a vertically-moving big vehicle, and the key construction points of the vertically moving big vehicle are that: the vertically-moving big vehicle is provided with a crossbeam, the crossbeam is provided with a horizontally-moving small vehicle, the bottom of the crossbeam is provided with a horizontal track, the horizontal track is provided with an electric hoist, a frame is arranged on the horizontally-moving small vehicle, a cylindrical upper material bin is arranged on the frame, a lower material bin, whose top part is an opening and bottom part is a material outlet, is arranged in the upper material bin, the lower material bin is arranged on the frame through a lifting mechanism, the bottom part of the frame is provided with a lower frame, a quantitative material bin is arranged on the lower frame, and a vibration material sieving box is arranged between the quantitative material bin and the material outlet of the lower material bin through a soft connection.