The invention discloses aluminum-strengthened maraging steel and a preparing method of the aluminum-strengthened maraging steel. The aluminum-strengthened maraging steel comprises, by weight percent, 0.01% to 0.2% of C, 6% to 24% of Ni, not larger than 6% of Mo, 0% to 4% of Mn, 0.5% to 6% of Al, 0% to 12% of Cr, 0% to 1.5% of Nb, 0% to 4% of Cu, 0% to 3% of W, 0.0005% to 0.05% of B and the balance Fe and inevitable impurities. Smelting is carried out according to ingredient compositions, and through forging, solid solution treatment and cold rolling heat treatment processes, the maraging steel is prepared, wherein the structure of the maraging steel is uniform, a high-density B2-NiAl intermetallic compound is a main strengthening phase of the maraging steel, and micro carbide and nanoclusters conduct joint strengthening on the maraging steel; and the maraging steel shows the excellent mechanical property, the tensile strength can reach 2.2 GPa. In addition, the main strengthening phase NiAl and a base body are in a coherent relationship, and the elasticity modulus and the base body are basically consistent.