In the incipient stage inter-turn short circuit fault detectionthe fault signal cannot be detected because the amplitude of fault characteristic frequency is very small and it is easy to be interfered by noise signal. To solve the above problemsa method based on variational mode decomposition (VMD) and double logarithmic spectrum analysis is proposed for the incipient stage inter-turn short circuit fault detection of permanent magnet synchronous motor (PMSM). The VMD is applied to remove the noise and related harmonic components in zero sequence voltage component (ZSVC) for highlighting the fault characteristic component. Thenthe double logarithmic spectrum analysis method is used to analyze the obtained signal for inter-turn faultand the fault of inter-turn short circuit can be judged by detecting the fault characteristic frequency in the spectrum diagram. The effectiveness of the proposed fault detection method is validated by the simulation and physical test.