The invention provides a cold extrusion molding device for an aluminum alloy seamless tube. The cold extrusion molding device for the aluminum alloy seamless tube is characterized in that a lower mould I with a center hole, and a lower mould II with a center hole are sequentially upwards mounted on a bottom board; a core rod type hydraulic cylinder is arranged in the center of an upper mould board; beam type hydraulic cylinders are respectively mounted at two upper sides of the upper mould board; a piston rod of the core rod hydraulic cylinder is downwards connected with a core rod; piston rods of the two beam hydraulic cylinders are downwards connected above a beam; the center of the beam is downwards connected with an upper mould with a center hole; the core rod passes through the center hole of the upper mould; and the lower end of the upper mould and the center hole of the lower mould I are matched. By using the cold extrusion molding device for the aluminum alloy seamless tube, provided by the invention, to machine the aluminum alloy seamless tube, an aluminum alloy raw material has no need of being heated, and is molded by cold extrusion at a constant temperature state. With the adoption of a vertical type hydraulic machine, an upper mold and a lower mold are arranged at the lower part of the hydraulic machine, so that the aluminum alloy seamless tubes with different diameters can be formed by changing the diameters of inner holes of the two molds. The cold extrusion molding device for the aluminum alloy seamless tube has the advantages of low cost, high machining efficiency, no need of heating, no need of consuming coal and electricity, emission reduction, and energy conversation and environment friendliness.