Abstract: The local demagnetization fault in permanent magnet synchronous motors (PMSMs) can cause abnormal vibrations and noise to machine, and even potentially leading to permanent damage. Thus, accurate detection of local demagnetization fault is of paramount importance. It is found that local demagnetization fault can induce local saturation in the stator iron core, subsequently leading to an increase in the inductance saliency. While this phenomenon is evidently absent in a uniformly demagnetized state. Based on this, this paper proposes a targeted detection approach for local demagnetization fault by extracting the high frequency (HF) fault features from the zero-sequence voltage of the motor under HF signal injection. An experimental platform is established to validate the method's effectiveness.