Hybrid Rotary Friction Welding is a modified type of common rotary friction welding processes. In this welding method, parameters such as pressure, angular velocity and time of welding control temperature, stress, strain and their variations which play an important rule in defining optimum process parameter combinations in order to improve the design and manufacturing of welding machines and quality of welded parts. Thermo-mechanical simulation of friction welding has been carried out. It has been shown that simulation is an important tool for prediction of generated heat and strain at the weld interface and can be used for prediction of microstructure and evaluation of quality of welds. For simulation of Hybrid Rotary Friction Welding a commercial finite element program has been used and the effects of pressure on temperature and strain variations have been investigated.