With the continuous advancement of aircraft electrification, Permanent Magnet Synchronous Motors (PMSMs) are widely used in various electrical drive systems on aircraft due to their excellent performance. Among the technologies of vector control, accurate identification of the initial rotor position is of great significance for the smooth starting and maximum torque operation for PMSMs. This paper provides a comprehensive overview of the initial rotor position identification methods for PMSMs from two perspectives: with and without position sensors. Firstly, the initial rotor position identification methods for PMSMs with position sensors are classified into two types: rotor standstill type and rotor micro motion type, and the similarities and differences of the identification methods of the rotor with position sensors are compared. Then, based on whether the injection signal is continuous or not, the initial rotor position identification methods for PMSMs without position sensors are divided into two categories: the high-frequency voltage injection method and the pulse voltage injection method. The pulsating high-frequency voltage injection method is selected to verify the effectiveness of rotor initial position identification. Finally, the development trend of initial position identification methods for PMSMs is discussed.