The invention discloses a partial discharge ultrahigh frequency detection system and method. The partial discharge ultrahigh frequency detection system comprises a high-voltage sleeve pipe, a disc type insulator, a sensor, an inflatable device, a water resistor, a high-voltage test transformer, a transformer, a partial discharge detector and a voltage divider, wherein the high-voltage sleeve pipe and the disc type insulator are vertically installed in a matched mode, the sensor is installed at one side of the disc type insulator, the inflatable device is installed at the other side of the disc type insulator, the water resistor, the high-voltage test transformer, the transformer and the partial discharge detector are connected among the high-voltage sleeve pipe, the disc type insulator and the sensor in sequence, and the voltage divider is connected between a shared end of the high-voltage sleeve pipe and the water resistor, and the ground. The partial discharge ultrahigh frequency detection system and method can overcome the defects of low reliability, a high erroneous judgment rate, a small application range and the like in the prior art, and has the advantages of being high in reliability, low in erroneous judgment rate and wide in application range.