The invention discloses a high-strength wear-resistant steel particularly suitable for a railway frog and a manufacturing method thereof. The steel is prepared by the following components in percent by weight: 0.29-0.45% of C, 0.20-0.59% of Si, 0.90-1.51% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, 1.52-1.79% of Cr, 1.01-1.49% of Ni, 0.29-0.59% of Mo, 0.02-0.07% of Al, 0.025-0.10% of Nb, greater than or equal to 0.05% and less than or equal to 0.15% of Nb + Al, less than or equal to 20 ppm of [O], less than or equal to 100 ppm of [N] and less than or equal to 0.50 ppm of [H], and the balance of iron and other unavoidable impurities. A manufacturing method for an alloy steel comprises the following steps: electric arc furnace smelting, ladle furnace refining, vacuum furnace degassing, die casting, blooming cogging, forging forming, dehydrogenation thermal treatment and final thermal treatment. Compared with the prior art, the alloy steel disclosed by the invention has the advantages that the strength is high, the wear resistance is excellent, the toughness is high, and the inner quality is stable and uniform.