High-sulfur petroleum coke is used for gasification, which can realize the efficient and clean utilization of petroleum coke. The entrained flow co-gasification of coal and petroleum coke is the common technical route of petroleum coke gasification. Compared with coal, the content of V element in petroleum is higher, which is easy to cause the corrosion of refractory materials. The refractory materials of chromium-free are developing at present, there is few researches on the erosion of slag containing V on new type refractory materials. A typical gasification coal ash was selected, which was mixed with V2O5 to simulate co-gasification ash of petroleum coke and coal. The corundum refractories with broad application prospects were used for corrosion test. The influences of V element content, reaction temperature and reaction time on the degree of erosion were investigated. XRD was used to analyze the evolution of minerals in slag containing vanadium at the high temperature process. The changes of morphology and surface during the corrosion process of V containing slag and corundum materials were analyzed by SEM. The erosion mechanism of slag containing V to corundum materials was clarified. The resultsshow that the V element in the slag forms vanadium aluminum spinel at the interface of corundum materials. The mutual substitution of V element and Al element in the slag forms an interactive reaction layer that erodes the surface of the material, which weakens the compactness of the corundum material surface. The penetration of the low viscosity liquid slag in corundum is intensified. With the reaction temperature increasing, the reaction between V element and Al2O3 of corundum is intensified, the size of crystalline spinel particles at the interface of corundum material increases, and the compactness of the reaction layer decreases, which accelerates the liquid slag with low viscosity penetrating into the corundum material, resulting in the erosion of corundum material aggravating. When the V content increases, the thickness of the reaction layer between the slag and corundum material increases, and the interaction interface becomes more irregular, resulting in a significant increase in the corrosion degree of corundum material. The penetration of liquid slag intensifies as the reaction time increases, This leads to the significant increase of the erosion degree of corundum material. The corrosion degree of corundum material also increases obviously with the reaction time increasing, as the penetration degree of liquid slag increases. V content is the most critical factor to determine the degree of corrosion. When the mass fraction of V2O5 in slag is 10%, and the reaction temperature is 200 ℃ higher than the flow temperature, the corundum material is most seriously eroded. When petroleum coke is gasified with coal, the V content and the operating temperature should be strictly controlled to avoid aggravating the erosion of refractory materials.