In thermal flow-reversal reactor operations, honeycomb ceramic regenerators are exposed to thermal shock load. In this study, numerical simulations of the temperature and thermal stress distributions of honeycomb ceramic regenerators are carried out using the CFX software. Temperature variations with time are calculated first for honeycomb ceramic regenerators with holes of different shapes. Then, thermal stress distributions of regenerators are analyzed with different structural and operational parameters. The analyses show that the thermal stress of honeycomb ceramic regenerator depends on the shape of holes, porosity and wall thicknesses. This study provides a theoretical basis for optimization of honeycomb ceramic regenerators.