A method for preparing acrylic acid comprising the steps of: subjecting glycerin to a dehydration reaction in the presence of at least one catalyst selected from the group consisting of ZrZn 0.02 W 0.1 P 2 H x O y, Zr 0.9 Fe 0.1 W 0.1 P 2 H x O y, Zr 0.9 V 0.1 W 0.1 P 2 H x O y, Zr 0.9 Nb 0.02 Fe 0.1 W 0.1 P 2 H x O y, Zr 0.9 Zn 0.02 Fe 0.1 W 0.1 P 2 H x O y, Zr 0.9 Zn 0.02 V 0.1 W 0.1 P 2 H x O y, Zr 0.8 Zn 0.02 (FeV) 0.1 W 0.1 P 2 H x O y, Zr 0.8 Zn 0.02 Fe 0.2 W 0.1 P 2 H x O y, Zr 0.8 Zn 0.02 V 0.2 W 0.1 P 2 H x O y, and Zr 0.95 Zn 0.02 V 0.05 W 0.1 P 2 H x O y, x is 2 to 6, and y is 1 to 3, and oxygen or air; and carrying out a partial oxidation reaction of acrolein from a product obtained from the dehydration reaction, wherein the partial oxidation reaction is carried out in the presence of a catalyst represented by Chemical Formula 2 below and oxygen or air: [Chemical Formula 2] Mo l W m V n (M 3) q (M 4) r O z in Chemical Formula 2, M 3 is Fe, Cu, Bi, Cr, Sn, Sb, or K, M 4 is an alkaline earth metal, l, m, n, q, r, and z represent an atomic ratio of Mo, W, V, M 3, M 4 and O, respectively, wherein I is 5 to 15, m/l is 0.15 to 0.4, n/l is 0.1 to 0.5, q/l is 0.1 to 0.4, r/l is 0 to 0.2, and z is a value determined according to the oxidation state of another element wherein in the dehydration reaction, a content of oxygen in a gaseous reactant is 3.5 to 12 mol%, and a molar ratio of oxygen to glycerin (oxygen/glycerin) is 1 to 1.75. subjecting glycerin to a dehydration reaction in the presence of at least one catalyst selected from the group consisting of ZrZn 0.02 W 0.1 P 2 H x O y, Zr 0.9 Fe 0.1 W 0.1 P 2 H x O y, Zr 0.9 V 0.1 W 0.1 P 2 H x O y, Zr 0.9 Nb 0.02 Fe 0.1 W 0.1 P 2 H x O y, Zr 0.9 Zn 0.02 Fe 0.1 W 0.1 P 2 H x O y, Zr 0.9 Zn 0.02 V 0.1 W 0.1 P 2 H x O y, Zr 0.8 Zn 0.02 (FeV) 0.1 W 0.1 P 2 H x O y, Zr 0.8 Zn 0.02 Fe 0.2 W 0.1 P 2 H x O y, Zr 0.8 Zn 0.02 V 0.2 W 0.1 P 2 H x O y, and Zr 0.95 Zn 0.02 V 0.05 W 0.1 P 2 H x O y, x is 2 to 6, and y is 1 to 3, and oxygen or air; and carrying out a partial oxidation reaction of acrolein from a product obtained from the dehydration reaction, wherein the partial oxidation reaction is carried out in the presence of a catalyst represented by Chemical Formula 2 below and oxygen or air: [Chemical Formula 2] Mo l W m V n (M 3) q (M 4) r O z in Chemical Formula 2, M 3 is Fe, Cu, Bi, Cr, Sn, Sb, or K, M 4 is an alkaline earth metal, l, m, n, q, r, and z represent an atomic ratio of Mo, W, V, M 3, M 4 and O, respectively, wherein I is 5 to 15, m/l is 0.15 to 0.4, n/l is 0.1 to 0.5, q/l is 0.1 to 0.4, r/l is 0 to 0.2, and z is a value determined according to the oxidation state of another element wherein in the dehydration reaction, a content of oxygen in a gaseous reactant is 3.5 to 12 mol%, and a molar ratio of oxygen to glycerin (oxygen/glycerin) is 1 to 1.75. M 3 is Fe, Cu, Bi, Cr, Sn, Sb, or K, M 4 is an alkaline earth metal, l, m, n, q, r, and z represent an atomic ratio of Mo, W, V, M 3, M 4 and O, respectively, wherein I is 5 to 15, m/l is 0.15 to 0.4, n/l is 0.1 to 0.5, q/l is 0.1 to 0.4, r/l is 0 to 0.2, and z is a value determined according to the oxidation state of another element wherein in the dehydration reaction, a content of oxygen in a gaseous reactant is 3.5 to 12 mol%, and a molar ratio of oxygen to glycerin (oxygen/glycerin) is 1 to 1.75.