The invention relates to a heat-resistant abrasion-resistant double-phase stainless steel casting alloy material, and belongs to the technical field of steel and iron alloy materials. The heat-resistant abrasion-resistant double-phase stainless steel casting alloy material comprises the following components in percentage by mass: 0.15-0.45% of C, 25.0-28.0% of Cr, 4.0-6.0% of Ni, 0.5-1.0% of Mo, 0.05-1.5% of Nb, less than or equal to 1.0% of Mn, less than or equal to 1.5% of Si, less than or equal to 0.03% of P, less than or equal to 0.03% of S, less than or equal to 0.5% of C+N, less than or equal to 1.5% of Nb+V, and the balance of Fe and inevitable impurities. A solid-solution structure of the steel in the component range comprises ferrite and austenite, wherein the austenite accounts for 40-60%, the room-temperature tensile strength is 500-700 MPa, and the elongation percentage is more than 20%. The alloy material is prepared by a conventional smelting process method comprising the following steps: smelting ingredients, performing cast molding, performing solid-solution treatment at 1000-1200 DEG C and aging treatment at 700-900 DEG C, and performing mechanical processing. The alloy material has very good abrasion resistance at 650-950 DEG C and is a relatively good candidate material for manufacturing a mechanical grate for a garbage power station.