Horseshoe-shape erosion and poor tightness would occur when casting the Al2O3-C and Al2O3-ZrO2-C sliding plate for steel calcium treatment.Mechanism of damage to the Al2O3-ZrO2-C sliding plate by the calcium treatment steel during casting is analyzed in details.Al2O3-MgO-C sliding plate is developed through burning,oil immersion,and drying,which is mainly made from fused magnesia,Al2O3-MgO spinel and corundum,etc.as raw material.The diameter of the sliding plate hole is also optimized.As a result,erosion resistance of the sliding plate is effectively improved,which can be used much more times.