Abstract: The temperature/stress distribution in the porous plug for ladle furnace was investigated using ANSYS software. The results showed that the surface temperature of the plug is the same to the molten steel, while the temperature in the plug changes with working time, no matter where it is. Inside the plug the temperature comes up to its maximum and down to its minimum when the working time is 15 min and 60 min, respectively, then it starts to rerise gradually with increasing working time. The stress near the plug surface is highest with high axial stress gradient, i.e., higher than 80 MPa at plug surface but about 50 MPa at the depth of 0.005 m as calculated from the surface. The laminar spalling due to the thermal stress near plug surface is the basic cause of the damage to the plug.