This paper studies the failure of high chrome brick used in opposed four-nozzle gasifier.The scan electron microscopy (SEM) analysis result shows that firstly there is almost no slag in the interface of slag/brick of high chrome brick and a  ZrO2-free layer with a depth of about 3 mm under the interface,secondly the FeO in slag reacts with the Cr2O3 in brick to form ferrochrome spinel (FeCr2O4),which focuses in the ZrO2-free layer interface,thirdly the SiO2 and CaO of the slag infiltrate deep into the brick and react to form low melting point material mainly such as calcium aluminum silicate and a small amount of calcium phosphate,and finally the failure forms of high chrome brick used in gasifier are mainly infiltrated erosion and spalling.