The Korea Geostationary Ocean Color Imager (GOCI) onboard COMs-1 (Communication, Ocean & Meteorological Satellite-1) is mainly designed for ocean observation, and it has a good potential for land monitoring. Cross calibration between GOCI and the US Moderate Resolution Imaging Spectrometer (MODIS) can improve the land radiation characteristics of GOCI, which can expand its ability in land observation. In cross calibration, the effects from spectral response of two sensors are considered and the impacts of the differences between GOCI and MODIS viewing angles in calibration are revised by radiative transfer simulation. Meanwhile, satellite data in the same transit time of two sensors are chosen in order to reduce the effects from different sun zenith angles. Cross calibration results show that the simulated top of atmosphere (TOA) radiance from MODIS agrees well with GOCI measured TOA radiance, and the value of R2 is greater than 0.88. Preliminary validation of calibration results shows that the cross calibration method can meet the accuracy requirements of general quantitative remote sensing applications.