The invention discloses a processing method and device for a multi-stage resonance of high-voltage main transformer. The processing method comprises the following steps of intelligently judging whether the main transformer encounters a resonant situation or not according to current information quantity of the high-voltage main transformer; comparing a resonant level value with a preset value; and sending a resonance processing instruction of the high-voltage main transformer according to a comparison result, so that the purpose of resonance damage is achieved, and a resonant point is prevented from being damaged by manually operating a series compensation device. Whether resonance is generated or not and the resonant level are intelligently judged, the resonance of the main transformer is processed by a mode of sending the instruction, the problems of manual operation, hysteresis and the like do not exist, and thus, the potential risk of a device such as the main transformer is rapidly eliminated.