Low cement Al2O3-SiO2 castables was prepared using super grade bauxite (w(Al2O3)＞85%) as aggregate, brown fused corundum, silicon carbide, Secar 71 CA cement, α-Al2O3 micropowder and microsilica as fine powders. The influence of SiC （0, 5 wt%, 10 wt%, and 15 wt%）on resistance to PbO rich slag was investigated by static crucible slag test （1 300 ℃ for 5 h, in air）. The slag corrosion mechanism of the castables was analyzed by means of SEM, EDS and XRD. The results show that the resistance of Al2O3-SiO2 castables to PbO rich slag is improved obviously by the addition of SiC. The corrosion mechanism of the PbO rich slag can be discribed as that PbO in the slag reacts with SiO2 and CaO in Al2O3-SiO2 castables, forming low melting compounds (such as PbO·SiO2 and 2PbO·SiO2).