The invention discloses a power equipment fault monitoring method based on a mutual reconstruction single-class auto-encoder.The method comprises the following steps: preprocessing acquired magnetic field information of power equipment in normal operation to obtain a training data sample set, training K mutual reconstruction single-class random auto-encoders WSI-GAE by taking the training data sample set as input to obtain a final encoding result, performing single classification model training by using regularized least square single classification loss, obtaining a fitting error of each trained data sample, and selecting a threshold from fitting error sequences of the data samples arranged from large to small, for newly collected magnetic field information data of the power equipment, the obtained fitting error is compared with a threshold value, and when the fitting error is larger than the threshold value, it can be judged that the power equipment has abnormal conditions such as faults. According to the invention, a single-class classifier technology is used to realize anomaly detection, and the method is more suitable for the target of the invention. The fault abnormity monitoring accuracy of the power equipment is improved.