The present invention discloses a positioning device and positioning method of a partial discharge source of an electrical device. The positioning device comprises a pressure differential vector sensor, a high-frequency carrier communication module and an analysis device. The pressure differential vector sensor is arranged in the insulating oil of the electrical device and configured to collect discharge information; the high-frequency carrier communication module is configured to send the transmission information of the pressure differential vector sensor to the analysis device; and the analysis device is arranged in a control chamber and configured to perform analysis of information collected by the pressure differential vector sensor to obtain the concrete position of the partial discharge source. The positioning device and positioning method of a partial discharge source of an electrical device are used for positioning the partial discharge source in the insulating oil of the electrical device, with simple structure, convenient usage and accurate positioning.