The invention relates to an antioxidant heat-resisting alloy and a preparation method and belongs to the technical field of alloys. The invention aims to solve the problems of high oxygen, sulfur andnitrogen contents, low proportion of Al2O3 film in the oxidation film on alloy surface, high aluminum content and low alloy toughness of the present alloy. The antioxidant heat-resisting alloy provided by the invention comprises the following components by weight percent: 2.5%-6% of Al, 24%-30% of Cr, 0.3%-0.55% of C, 30%-50% of Ni, 2%-8% of W, 0.01%-0.2% of Ti, 0.01%-0.2% of Zr, 0.01%-0.4% of Hf,0.01%-0.2% of Y, 0.01%-0.2% of V, less than 0.05% of N, less than 0.003% of O, less than 0.003% of S, less than 0.5% of Si and the balance of Fe and inevitable impurities, wherein only one of Ti andV exists. The preparation method for the antioxidant heat-resisting alloy comprises the following steps: smelting inactive element materials, refining, adding misch metal, adding slag and alloying theinactive elements. The full antioxidant temperature of the antioxidant heat-resisting alloy provided by the invention reaches up to 1200 DEG C and the alloy can long-term stably serve at 1200 DEG C or above.