In steelmaking process,the refractories are eroded by molten steel.In this paper,corundum castable and alumina-magnesia castable are prepared with tabular corundum and magnesium corundum as aggregates,α-alumina and magnesia as fines,erosions of molten steel to different refractories are studied with the method of static sample immersion ventilation.The results show that the occurrence of refractory erosion depends on the critical erosion strength of the material.With  the  increase of blowing volum,erosion occurs when the shear stress is higher than the critical shear strength.Erosion begins with the matrix part of the refractory material until the aggregate peels off.Alumina-magnesia refractory had better erosion resistance than tabular corundum refractory.