Abstract: The skirt support structure of the hydrogenation reactor has big mechanical stress and thermal stress, and poor stress state. This paper analyzes the temperature field of the skirt support structure of the hydrogenation reactor and the thermal stress through indirect analysis method of adding the temperature field to the structure. Based on the one directional tensile test of different temperature points, the stress-strain curve of material under different temperature points is obtained, and materials constitutive of linear elastic and elastic-plastic are used to carry out the finite element calculation of the skirt support structure of the hydrogenation reactor. Comparison and analysis of the results show that the calculation result of elastic-plastic finite element is more accurate. Besides, based on the failure evaluation content of these two methods in ASME Ⅷ-2 2007, this paper evaluates and calculates the possibility of local failure in this structure. The research in this paper indicates that the calculation results based on linear elastic finite element can be used in the engineering design, but the most stress position may not be the same position in the actual situation, which means that there is still margin for the improvement of the analysis and design calculation method.