Silicon carbide (SiC), as a typical representative of the thirdgeneration semiconductor material, has performance advantages in wide band gap, high thermal conductivity, high breakdown electric field and large electron drift velocity, etc., and is considered to be one of the ideal materials for high temperature, high frequency, high power and high voltage devices. SiC can effectively break through the physical limits of traditional Sibased power semiconductor devices, known as a green energy device that drives the “new energy revolution”. As the core material for the manufacture of power devices, the growth of SiC single crystal substrate is very important, especially the preparation of single 4HSiC polytype. Due to the better crystallographic compatibility and similar formation free energy among different polytypes, the grown SiC bulk crystals are prone to produce polytype inclusions and then seriously affect the device performance. Therefore, in this paper, the basic principle, growth process and existing problems of SiC crystal prepared by physical vapor transport (PVT) method are summarized firstly. Then the possible inducing factors for the formation of polytype inclusions were given and the relevant mechanisms are also discussed. In addition, the common identification methods of SiC polytype structures are further introduced. Finally, a prospect for the research of SiC single crystal are made.