Abstract: Flat wire winding has emerged as a leading winding form for traction motors in electric vehicles (EVs) owing to its advantages such as high slot fill factor, good heat transfer performance, and low vibration and noise. However, as electric drive systems progress towards higher frequencies and voltages, flat wire winding encounters many challenges. This paper summarizes the status of flat wire winding from the aspects of structure, AC loss, thermal management, cooling, insulation and manufacturing technology. First, the topology and design principle are introduced, the mechanisms of AC loss are expounded, and the calculation model and suppression method are summarized. Subsequently, the heat distribution of flat wire winding motor is given, and different cooling schemes are compared. Furthermore, based on the research status of insulation problem, a high reliability design method for flat wire winding considering the effect of thermal and voltage stress coupling is proposed. Finally, the next generation of flat wire winding manufacturing technology including the potential integration of 3D printing is prospected, and concluded by outlining future development trends of flat wire winding.