A ferrite low-density high-strength steel and manufacturing method thereof. The ferrite low-density high-strength steel chemical comprises the following chemical components composition by mass percentage: 0.05-0.40% of C, 4.0-12.0% of Mn, 3.0-7.0% of Al, no more than 0.02% of P, no more than 0.01% of S, no more than 0.01% of N, and the balance of Fe and inevitable impurity elements. The above elements satisfy the following relationship: 1.0<Mn / Al, 3.5 <1.5Mn / Al+10C, and Mn / Al + 10C <5.2 The manufacturing method comprises hot rolling, annealing, pickling, cold rolling and annealing to prepare the low-density high-strength steel plate. In addition to ferrite, the microstructure of the steel plate also contains 6-40% of residual austenite. The low-density high-strength steel plate has tensile strength no less than 800MPa, elongation no less than 25%, and density less than 7500kg / m<3>.