The invention relates to the field of aluminum alloys and discloses an aluminum alloy and a preparation method and application of the aluminum alloy. The aluminum alloy comprises, by weight percent, 9%-12% of Si, 1%-2.5% of Zn, 0.6%-1.5% of Mg, 0.3%-1% of Mn, 0.5%-1% of Fe, 0%-0.5% of adding elements and 73.7%-90% of aluminum, and the adding elements are at least one of Ti, Zr, Cr, Cu, Bi, Ni and Sr. By means of the ratio, the aluminum alloy has good casting performance and excellent mechanical performance and meanwhile has high thermal conductivity.