The lunar irradiance reflected from the sun is a benchmark for radiance calibration in the visible and near-infrared spectra. Lunar calibration has become a new method to calibrate and validate satellite-based instruments. The Moderate Resolution Spectral Imager（MERSI） on FY-3C adds a function to monitor the lunar disk to improve the on-orbit calibration of solar reflective bands（SRB） for the MERSI. In this study

11 groups of the dataset have been collected to record the lunar measurements since the launch of the FY-3C. With the ratio between the target channel and the referred channel

the effects of the lunar phase angle and the relative distance of the solar–lunar satellite have been removed from the measured lunar irradiance. The SRB of the MERSI in the visible and near-infrared spectra have been calibrated from the lunar measurements. The long-term trend of the SRB of the MERSI has been analyzed. The annual attenuation rate has increased to14.55% and 8.42% for bands 8 and 9

respectively. The annual attenuation rate is between 1.15% and 4.72% for bands 1

6

10

11

16

and19. No attenuation is observed for the rest of the bands. The aforementioned results can be used to correct the systemic bias of the radiance calibration of the MERSI. The accuracy of the radiance calibration of the MERSI can be improved on basis of the lifetime of the instrument.