The invention provides a GIS partial discharge ultrahigh frequency live-line detection method. The GIS partial discharge ultrahigh frequency live-line detection method is characterized in that S1, an ultrahigh frequency sensor is used to receive electromagnetic pulse signals generated by GIS partial discharge, and the electromagnetic pulse signals can be converted into high frequency voltage signals, and then can be transmitted to a partial discharge detector by a shielding cable; and at the same time, a wireless power frequency signal generating device is used to transmit power frequency voltage signals to the partial discharge detector; S2, the partial discharge detector is used for the data analysis of the high frequency voltage signals and the power frequency voltage signals to acquire a PRPD discharge map and an ultrahigh frequency discharge pulse waveform; S3, the partial discharge detector is used for the PRPD cluster analysis and the pulse waveform time frequency analysis of the PRPD discharge map and the ultrahigh frequency discharge pulse waveform, and according to the analysis result, the discharge type of the GIS partial discharge can be identified. By adopting the technical scheme provided by the invention, the GIS partial discharge ultrahigh frequency live-line detection method is advantageous in that the structure is simple, the operation is convenient, and the accuracy and the reliability of the GIS partial discharge detection can be improved.