590-MPa-level high-strength low-content-alloy hot-rolled acid-washed strip steel is disclosed. The strip steel includes, by weight, 0.05-0.1% of C, not more than 0.1% of Si, 0.8-1.5% of Mn, not more than 0.02% of P, not more than 0.008% of S, and 0.01-0.05% of Nb, with the balance being Fe and unavoidable impurities. A microcosmic metallographic structure includes ferrite and pearlite, wherein thevolume ratio of the ferrite is greater than 95%. The tensile strength of the strip steel is not less than 590 MPa, and the hole expansion rate [lambda] is not less than 65%. Through the component design, a special ferrite-pearlite structure is obtained, existence of the pearlite does not worsen forming performance, growth of ferrite crystal grains is significantly inhibited, ferrite crystal grains the dimension of which is 6 [mu]m or below are obtained, and forming performance is improved. Compared with similar ferrite-pearlite steel, a product prepared by the method has sufficient strength and has excellent hole-expanding and flanging properties.