Magnesia-spinel bricks are prepared using fused magnesia and spinel as the main raw materials, formulated according to a close-packed particle size distribution, uniformly mixed, high-pressure formed, and subjected to low-temperature baking treatment. Magnesia-spinel bricks are used as refractory lining in RH furnaces for molten steel refining, featuring environmentally friendly and pollution-free characteristics, high-temperature strength, excellent resistance to slag erosion and slag infiltration, good volume stability, and superior thermal shock resistance, compared to magnesia-chrome bricks.