The application discloses partial discharge detection device includes: a super sound wave resonance sensor for gathering high -frequency ultrasound signal that partial discharge produced, link to eachother with super sound wave resonance sensor, be used for to carry out filtering and enlarged preprocessing circuit with the high -frequency ultrasound signal, link to each other with preprocessing circuit, be used for to judge whether the high -frequency ultrasound signal exceedes the treater of predetermineeing the threshold value, link to each other, be used for with the treater to judge the high -frequency ultrasound signal above predetermineeing the alarm device that the threshold value was then reported to the police when the treater. Ultrasonic sensor collection high -frequency ultrasound signal is passed through in this application, carries out filtering by preprocessing circuit to the high -frequency ultrasound signal and with enlarged, calculates the high -frequency ultrasound signal volume of reaching partial discharge by the treater again, and judgement partial discharge measures whether exceed predetermined threshold value, if exceed, then send alarm information to alarmdevice to make alarm device report to the police, whether partial discharge takes place for alright real -time on line measurement high voltage insulation electrical equipment thereby the realizationneed not be cut off the power supply, thereby has guaranteed the safety of circuit.