The invention relates to a sulfur hexafluoride gas insulation totally-enclosed combined electric partial discharge detection and positioning system in order to conveniently detect and position the insulation defects of a gas insulation switch device from the outside. A central control unit is connected with an ultrahigh frequency signal receiver and an ultrasonic receiver; if a measured ultrahighfrequency signal and ultrasonic have continuous correlation, the position of the ultrasonic receiver on the external wall of the gas insulation switch device is changed for a plurality of times, and the time difference of maximum amplitude appearing in the amplitude characteristic map of ultrahigh frequency signals and maximum amplitude appearing in the amplitude characteristic map of ultrasonic on each detection position is recorded so as to calculate the distance between a discharge point and each detection position; and the position of the insulation defect in the gas insulation switch device is calculated according to the external dimension of the insulation switch device.