The invention relates to a brightness meter calibration device, which comprises a dial, a supporting frame supporting the dial, and two level meter connecting pieces, wherein the dial comprises a body, and the body is provided with at least two scale lines with an included angle of 45 degrees; and the two level meter connecting pieces are arranged on the supporting frame, and can move relative to the supporting frame, so that the two level meter connecting pieces can be adjusted to align with the two scale lines with the included angle of 45 degrees separately. According to the brightness meter calibration device, two level meters can be connected with the two level meter connecting pieces separately, the two level meter connecting pieces can align with the two scale lines with the included angle of 45 degrees separately through adjusting positions of the two level meter connecting pieces on the supporting frame, and light emitted by the two level meters are aligned with a standard lamp and a brightness meter to be detected separately, thus the standard lamp and the brightness meter to be detected can be controlled to form an included angle of 45 degrees precisely; meanwhile, the standard lamp and the brightness meter to be detected are kept on the same level by means of the horizontal line function of the level meters, thereby guaranteeing high calibration precision of the brightness meter.