Abstract: To investigate the effects of contact and axial power on the thermodynamic performance of the heat pipe cooled reactor core, a thermal-mechanical coupling program was developed based on the FEniCS platform. The program uses a simplified method to solve 2D and 3D contact pressure, primarily including gap heat transfer, linear elastic mechanics, and multidimensional contact pressure solution models. Taking the MegaPower reactor as the subject, the study first validated the accuracy of the program using ANSYS, and then a thermal-mechanical simulation of the core was performed to analyze temperature and Mises stress fields. The results indicate that when considering contact, the peak temperature of the fuel pin significantly decreases and the Mises stress decreases slightly; the peak temperature of the monolith changes little, but the Mises stress increases markedly. The axial power mainly affects the Mises stress of the fuel pin, while the Mises stress of the monolith is primarily influenced by contact pressure.