This paper presents a methodology for radiometric cross-calibration of the solar reflective spectral bands of Moderate Resolution Imaging Spectroradiometer (MODIS) and Chinese Moderate Resolution Imaging Spectroradiometer (CMODIS) sensors based on analysis of two difference time image pair for Dunhuang test site on July 27, 2002. With the well-calibrated MODIS as a reference, we derive top-of-atmosphere(TOA) reflectance using MODIS data and then use these TOA reflectance to compute TOA radiance for CMODIS taking into account the effect of spectral band different and the changes in solar zenith angle due to any temporal differences in the overpass times as well as differences in the view angles between the sensors. This TOA radiance, which is correlated with the sensor digital number (DN) output, determines the in-flight calibration coefficients of CMODIS. The relatively error between the cross-calibration and the reflectance-based method calibration results is within 9%.