Cr2O3 has eminent slag corrosion resistance. So, the magnesite-chrome brick is thought as an important refractory material used in RH refining furnace in the process of steel-making around the world. After chrome-bearing sols being prepared by sol-gel method, single sol (Cr(OH)3) and mixed sol (Mg(OH)2-Cr(OH)3) were impregnated into magnesite-chrome bricks by vacuum impregnation. The corrosion resistance of the impregnated bricks to silicon steel slag was studied by porosimetric analysis and fractal dimension calculation. The results showed that the corrosion resistance of impregnated magnesite-chrome brick was better than that of the unimpregnated brick and the brick impregnated by MgSO4 solution, and the one which has surface-treated by Mg(OH)2－Cr(OH)3 sol was the best, mainly because of lower apparent porosity, smaller pores diameter and their smoother inner surface.