The invention relates to a transformer substation partial discharge locating method based on spatial spectrum unambiguous estimation. The transformer substation partial discharge locating method is technically characterized by comprising the following steps that a uniform circular array is selected as an ultrahigh frequency antenna array; the acquired partial discharge signals are focused by usingthe least square algorithm; the azimuth angle and the pitch angle of a partial discharge source are calculated by using a multi-signal classification algorithm based on the fourth-order cumulant; andthe position of the antenna array is changed and the electric power equipment having partial discharge is determined. Transformer substation partial discharge is located by using the method based onspatial spectrum unambiguous estimation so that partial discharge detecting and locating of all the electric power equipment in the open transformer substation can be realized; besides, the detectingsystem has small size and has no problem of direction finding ambiguity so that the problems that the present partial discharge detecting system based on the ultrahigh frequency antenna array has large size and inspection is not implemented easily can be effectively solved, the cost of the large installing equipment state online detecting device can be greatly reduced and the detecting efficiencycan be enhanced.