The invention discloses a preparation method of an aluminum rod. The preparation method comprises the following steps that (1), an aluminum material conforming to a standard is selected and placed ina smelting furnace for melting, and slags on the furnace of molten aluminum is fished up; (2), the molten aluminum is introduced into a heat preservation furnace filled with nitrogen for heat preservation, and a purification flux is added; (3), molten aluminum obtained in the step (2) is conveyed to a continuous casting machine to be cast into an aluminum ingot; (4), the aluminum ingot obtained inthe step (3) is rolled into the aluminum rod through a continuous rolling machine; (5), the rolled aluminum rod passes through a cleaning and cooling pipeline, and the temperature of the aluminum rodis reduced to be 80 DEG C or less than 80 DEG C; (6), the aluminum rod is conveyed to a winding machine for winding; and (7), the aluminum rod is packaged and tested, sent out through a travelling crane, and weighed and warehoused. The preparation method is simple in process, capable of greatly saving the cost, capable of ensuring the uniformity of the tensile strength of the aluminum rod, and capable of producing the aluminum rod with high conductivity and high strength.