Abstract: High speed permanent magnet machines（HSPMMs） have a promising future in applications such as aeronautics and astronautics, energy and ultra-precision manufacturing. This paper enumerates various stator and rotor structures and materials of the HSPMM in literature. Then different losses in the HSPMM are summarized in aspects of stator iron loss, copper loss, rotor eddy current loss and air friction loss. Various motor temperature rise calculation methods and three kinds of high speed rotor bearings are compared, followed by an overview of the problems linked to the rotor strength and dynamics analysis. Finally, development trends of the HSPMM related technologies are summarized and prospected.