The invention discloses a high-strength and high-tenacity aluminum alloy and a preparing method thereof. The alloy comprises components including, by weight percent, 1.3%-2.06% of Mg, 6.18%-7.1% of Zn, 1.05%-2% of Cu, 0.07%-0.16% of RE, 0.08%-0.15% of Fe, 0.11%-0.23% of Si, 0.04%-0.12% of Zr, 0.01%-0.23% of Ti, 0.01%-0.03% of Cr, 0.1%-0.24% of Mn, 0.07%-0.14% of B, 0.11%-0.27% of Li, 0.28%-0.42% of Ag and the balance Al, wherein RE is one or more mixtures of Yb, Sc, Er, Y, Ce and La. The provided high-strength and high-tenacity aluminum alloy preparing method is simple in process, the obtainedaluminum alloy is high in strength, and tenacity and corrosion resistance are good.