Abstract: The reasons for poor weldability of aluminum/steel dissimilar metal welding metallurgy and rotary friction welding process, it was considered that rotary friction welding was the most suitable welding process of aluminum/steel dissimilar metal axisymmetric parts. Effects of continuous drive friction welding and inertia friction welding on the microstructure and properties of aluminum/steel dissimilar metals joints were introduced respectively. The main scientific problems that urgently need to be solved in the development of metal friction welding technology were summarized as followed. In rotary friction welding of aluminum/steel, the influence law and mechanism of violent plastic flow on IMCs generation at the friction welded interface and its vicinity need further study. It was necessary to develop a corresponding process to promote the formation of Fe-Al IMCs as the symbol of metallurgical bonding on the interface of aluminum/steel joint and to homogenize the thickness of IMCs layer. In the end, the study revealed the metallurgical behavior of aluminum/steel friction welded interface IMCs such as formation mechanism, phase composition, morphology and distribution, which were of great significance to control microstructure and properties of aluminum/steel rotary friction welded joint, and which were also the theoretical basis to guarantee the performance of aluminum/steel dissimilar metals welding structure.