Al2O3-Cr2O3 castable is one of the important lining materials of hazardous waste incinerators. However, the sources of hazardous waste are extensive and very complex, which lead to the difference of slag composition, thus affecting the service life of hazardous waste incinerators. In this paper, calcium aluminate cement (CAC) bonded Al2O3-Cr2O3 castable was taken as the research object. Three typical hazardous waste slags rich in CaO, Fe2O3 and SiO2 were selected, and the effects of the above hazardous waste slags on the erosion/penetration behavior and Cr(Ⅵ) formation of chromium corundum castables before and after firing were investigated. The result shows that the slag corrosion resistance and infiltration resistance of materials are related to the chemical composition of slag, viscosity, interfacial reaction between slag and materials and pore structure of materials. As far as infiltration is concerned, the high SiO2 slag and high Fe2O3 slag react with the material interface to form phases such as nepheline with low melting point, which promote the slag infiltration, while the high CaO slag reacts with the material to form phases such as CaAl12O19 with high melting point, which slow down the slag infiltration. As a result, the order of slag infiltration depth: high SiO2 slag>high Fe2O3 slag>high CaO slag. In contrast, heat treatment of the material can significantly reduce the reactivity of CaO in the matrix, microporation can be achieved, and the infiltration behavior of slag is inhibited, especially the infiltration of high SiO2 slag is significantly reduced. The corrosion resistance of static crucible slag is related to the infiltration behavior of slag liquid. Because of the obvious infiltration behavior of slag, the corrosion index of slag is reduced. After the high CaO slag reacts with the sample, the viscosity of slag liquid increases, and the calcium aluminate phase with high melting point is formed to slow down the penetration of slag liquid, and the time for slag to act on the material interface increases, which leads to the high corrosion index of high CaO slag.