Abstract: The friction welding using the energy stored in the flywheel to join parts is called inertial friction welding(IFW). In this method the flywheel was replaced by continual driving device, which makes the welding process more convenient to operate. In this paper, based on the former researches, the mechanical properties of IFW joints were summarized which include the micro-hardness, tensile strength, impact strength and some other aspects. The influence factors on joints properties were discussed emphatically. It is researched for the effects of such factors as the friction pressure, friction time, forge pressure and time during the welding which provides references for the later IFW research. Finally, the present existing problems were investigated for this kind of welding. Meanwhile future direction and the key research points were provided.