The utility model belongs to the field of temperature measurement, and discloses a fixing device for a thermal resistance temperature sensor probe. The fixing device comprises a connecting unit used for connecting a wire inlet of a transformer with a cable to be measured, and a fixing unit used for connecting a temperature measuring probe, the fixing unit is connected with the connecting unit, the fixing unit is an insulator, the fixing unit is provided with a probe jack and a connecting groove, and a heat transfer wall is arranged between the connecting groove and the probe jack; the connecting unit is provided with a connector, and the connector is arranged in the connecting groove and is connected with the heat transfer wall. According to the utility model, by arranging the thin insulating heat transfer wall between the temperature measuring probe and the connector of the connecting unit, current transmission between the cable and the temperature measuring probe is cut off, the influence, of current through the joint of the transformer and the cable, on the sensor temperature measuring probe is eliminated, the accuracy of the measurement is guaranteed, and furthermore the temperature of the joint of the cable can be measured accurately.