In order to meet the high-frequency on-orbit calibration requirements of the on-board load, the site automatic calibration technology is often used to invert the multi-spectral reflectance into the hyper spectral reflectance, so it is particularly important to improve the precision of automatic calibration to improve the inversion accuracy of spectrum. In this paper, we calculate the reflectance from September 2018 to September 2019 using a channel-type automated observation instrument deployed in the Dunhuang radiometric calibration site. Furthermore, we divide the data into 6 groups according to the difference in the solar zenith angles during the measurement process and employ the model of bidirectional reflectance distribution function (BRDF) for the consistency analysis of spectral shapes at different solar zenith angles. The experimental results show that the BRDF model is effective for correcting the data at different incident angles.