The invention provides a transformer bushing insulation partial discharge monitoring system and method. The method comprises the following steps of: sending out a discharge signal by a partial discharge source; sending out an ultrahigh-frequency electromagnetic wave signal by an ultrahigh-frequency sensor, and combining the ultrahigh-frequency electromagnetic wave signal with an ultrasonic signalsent by an ultrasonic sensor as auxiliary judgment signals; denoising a partial discharge signal, extracting an accurate partial discharge signal capable of reflecting a partial discharge problem in atransformer, and further extracting characteristic parameter information in the partial discharge signal; and finally, detecting a high-frequency current signal of a high-frequency current sensor, and judging whether a partial discharge signal exists in an internal insulation system of the transformer or not in combination with the ultrasonic signal sent by the ultrasonic sensor. According to theinvention, an electromagnetic vector sensor and an acousto-optic signal characteristic transformer partial discharge fault detection and positioning technology are utilized to establish a transformerpartial discharge detection method by combining inspection general measurement and accurate determination phase positioning.