The invention relates to the field of regeneration and utilization of waste refractory materials, particularly to a low-cost magnesia converter lining patching material and a preparation method thereof. The low-cost magnesia converter lining patching material is characterized in that waste refractory materials are taken as raw materials, and the patching material is formed by mixing the following components by weight parts: 80 to 95 parts of waste refractory materials, 8 to 20 parts of binding agent (asphalt), 0 to 10 parts of sintering aid (iron oxide red) and 0.1 to 5 parts of combustion improver (waste fuel oil); and the waste refractory materials are waste magnesia chrome bricks, waste magnesia carbon bricks or waste magnesia bricks. In the method for preparing the patching material, the waste refractory materials are proportionally mixed with asphalt and iron oxide red, and then 0.1 to 5 parts of combustion improver are added during the stirring process for uniform mixing. The invention has the benefits that the patching material and the preparation method thereof reduce the production cost of converter lining patching materials required for steel production, increase the economic benefits of steel enterprises, reduce the consumption of mineral resources, are energy-saving and environment-friendly and facilitate the sustainable development of enterprises and the nation.