The invention discloses a transformer fault probability calculation method based on operation state abnormal information. The method comprises: reading the operation state information of a transformer; analyzing the operation information of the transformer, and screening out various operation state abnormal signals; calculating a transformer fault probability according to a transformer fault probability calculation formula based on the abnormal information of the running state; and finally, sorting the fault probabilities of the related transformers from large to small to obtain a transformerfault set based on the abnormal information of the running state. The risk equipment fault set is output to the power grid on-line safety and stability evaluation early warning system so that subsequent evaluation of safety and stability of the power grid in the abnormal environment of the transformer operation state can be facilitated and safety and stability control measures can be given, and the safety and stability operation level of the power grid can be enhanced.