Abstract: According to the thermal-fluid-solid coupling analysis framework, the temperature field and stress field of the cylinder and the shaft of the high temperature pressurized roaster were simulated by using the direct coupling mode considering the bidirectional real-time interaction between fluid-solid and traditional unidirectional coupling mode. The strength of the cylinder and shaft was checked according to the first strength theory. The high-temperature creep model based on the Norton-Bailey and K-R damage theory of the cylinder was established, and the creep life was predicated. The results show that for the temperature field and stress field of the cylinder, the simulation by unidirectional coupling and direct coupling methods was similar, and the relative errors of the maximum temperature and the maximum stress were 0.0028 and 0.0069, respectively. For the temperature field of the shaft, the simulation by unidirectional coupling and direct coupling methods was similar, with the relative error of the maximum temperature being 0.0228. For the stress field of the shaft, the simulation of the maximum stress by the unidirectional coupling method were approximately 2.5 times that by the direct coupling method. According to the direct coupling and unidirectional coupling simulation, the maximum stress of the cylinder of the roaster with un-preheated raw materials exceeded the allowable stress; the cylinder failed the strength check. The maximum stress of the shaft was lower than the allowable stress; the shaft passed the strength check. Increasing the material inlet temperature could reduce the temperature difference at the inlet section of the cylinder and alleviate the stress. When the material inlet temperature was 350 ℃, the maximum stress of the cylinder was lower than the allowable stress; and the cylinder passed the strength checks. The high-temperature creep failure of the roaster cylinder was located at the inner area of the steam inlet obtained by simulation under the material inlet temperature of 350 ℃, and the service life was approximately 12.5 a.