The invention discloses a reinforced aluminum alloy with uniformly distributed graphene and a preparation method thereof. The reinforced aluminum alloy comprise, by weight, the following raw materialsincluding 5.0%-8.0wt.% silicon, 0.20%-0.50wt.% magnesium, 0.001%-0.007wt.% graphene, less than or equal to 0. 2wt.% zinc, less than or equal to 0. 1wt.% manganese, less than or equal to 0. 1wt.% titanium, less than or equal to 0. 15wt.% zirconium, less than or equal to 0. 1wt.% beryllium, less than or equal to 0.05 wt.% tin, less than or equal to 0. 1wt.% lead, other inevitable elements each of which is less than or equal to 0. 03wt.% and total of which is less than or equal to 0. 10wt.%, and the balance aluminum. The preparation method comprises the following steps that the raw materials areweighed, the raw materials are placed, a crucible is cleaned, and smelting, cooling and sampling are conducted. According to the method, the smelting condition is mild, process is simple and cost islow; and the graphene in the prepared aluminum alloy is uniformly distributed, the tensile strength, the yield strength and the elongation rate of of the aluminum alloy are all improved, and the application range is wide.