The invention discloses a homogenizing hexagonal aluminum alloy and a preparing method thereof. The preparing method of the homogenizing hexagonal aluminum alloy comprises the following steps that a hexagonal aluminum alloy casting ingot is subjected to heat preservation for 8-12 h under the temperature of 550-580 DEG C, then, cooling is performed, according to the cooling mode, air cooling is adopted at first to 300 DEG C, the cooling speed is 3-6 DEG C/min, then, spray cooling is performed to room temperature, the cooling speed is 5-7 DEG C/min, and the homogenizing hexagonal aluminum alloyis obtained. The relative area and the length-width ratio of Mg2Si eutectic phases remaining in homogenizing hexagonal aluminum alloy structures prepared by adopting the method and the average area and the length-width ratio of Al(Mn,Fe)Si phases are within the best range, and the aluminum alloy performance is better.