The present invention relates to a method and apparatus for on-line estimation of an initial position of a surface permanent magnet electric machine in a stationary state or at a first speed. The method (100) for on-line estimation of an initial position of a surface permanent magnet electric machine in a stationary state or at a first speed comprises: injecting a high-frequency pulsating voltage signal; acquiring a d-axis high-frequency current signal responding to the high-frequency pulsating voltage signal; and estimating an initial position of the surface permanent magnet electric machine on the basis of a second harmonic of the d-axis high-frequency current signal. According to the present invention, the apparatus (200) for on-line estimation of an initial position of a surface permanent magnet electric machine in a stationary state or at a first speed is also provided, the apparatus comprising a voltage injection unit configured to inject a high-frequency pulsating voltage signal, a current acquisition unit configured to acquire a d-axis high-frequency current signal responding to the high-frequency pulsating voltage signal, and an analysis unit configured to analyse a second harmonic of the d-axis high-frequency current signal so as to estimate an initial position of the surface permanent magnet electric machine.