Abstract: The fuel rods of pressurized water reactors operate under complex radioactive, thermal and mechanical conditions. Multiphysics have to be taken into account in order to evaluate their performance. Many existing fuel rod codes make great simplifications on analyzing the behavior of fuel rods. Based on the finite element method, a program evaluating the thermo-mechanical performance of pressurized water reactor fuel rod was developed. Steady-state analysis, transient analysis and reactivity insertion accident (RIA) analysis of fuel rods were carried out using the program. The results show that densification and swelling of the fuel caused by irradiation have an important influence on the fuel temperature. The swelling of fission products causes a noticeable increase of strain. The chamfers of pellets result in the occurrence of stress concentration at interface between the pellets. There is a significant influence in surface cracking of pellet if fuel rod power rapidly changes. The RIA causes the pellet to begin to rupture from the inside and leads to the pellet-cladding interaction.