The invention discloses an auxiliary temperature calibration device for a reaction cavity of a semiconductor film, and belongs to the field of semiconductor manufacturing. According to the auxiliary temperature calibration device, the light intensity of a light source can be adjusted to P0. Because the temperature, corresponding to P0, of the center of a blackbody furnace is T0, the light source can be equivalent to a heat radiation source with the temperature being T0. At the moment, the maximum value P0', detected by a temperature detection device, of the intensity of light, penetrating through a slit window, of the light source is equivalent to the heat radiation intensity obtained when the temperature in the reaction cavity of the semiconductor film is T0. When the auxiliary temperature calibration device for the reaction cavity of the semiconductor film is applied, the temperature detection device in the reaction cavity of the semiconductor film is calibrated under the condition that T0 and P0' are known. Thus, the light source can simulate blackbody radiation P0' when the temperature is T0, and support is provided for temperature calibration of the reaction cavity of the semiconductor film.