Beijing-1 microsatellite is the first applied earth observing microsatellite of China.Given that Beijing-1 multispectral sensors have no spectral functions,a new cross-calibration method war introduced to decrease the error caused by the spectral function and the imaging conditions.Based on five pairs near simultaneous images,which were taken by SPOT4/HRVIR2,Landsat5/TM and Terra/MODIS,Beijing-1 multispectral sensors were calibrated.The uncertainty of the cross-calibration is 8.32%,which is lower than that obtained by reflectance-based calibration based on calibration site.The result is acceptable tanking that Beijing-1 multispectral sensors have no spectral response function.