The present invention discloses a high-voltage equipment state evaluation method, a high-voltage equipment on-line monitoring device evaluation method, a high-voltage equipment state evaluation apparatus and a high-voltage equipment on-line monitoring device evaluation apparatus. The high-voltage equipment state evaluation method includes the following steps that: acquired spectrograms are compared with an established typical spectrogram sample library, wherein the typical spectrogram sample library contains at least a variety of distorted type typical spectrograms; and whether the acquired spectrograms are distorted spectrograms or non-distorted spectrums is judged, when the acquired spectrograms are the distorted spectrograms, the distortion of the spectrograms is related to the fault of an on-line monitoring device, when the acquired spectrograms are the non-distorted spectrograms, the acquired spectrograms are used for judging the operating state of high-voltage equipment. With the methods and apparatuses of the invention adopted, the correct judgment rate of the operating state evaluation of the high-voltage equipment can be improved, and the operating state of the on-line monitoring device can be also monitored and evaluated.