To improve the precision and temperature range of the laser cladding t emperature measurement system based on CCD colorimetric thermometry,a new method is propos ed to perform temperature calibration by using RGB digital filtering.Take the te mperature rad iation image of the MIKON M390high temperature standard blackbody furnace in each 50℃ under diffe rent parameters. Then calibrate the color-CCD from 1000℃ to 1800℃ by colorimetric thermometry.Emissivity is firstly included in the undetermined coefficient K and then the correspondence function relation between parameter K and gray ratio is built by least square meth od to reduce the error caused by emissivity.The idea of equipping with RGB narrowband filters is put forward to do image acquisition an d color filtering processing,and then the mapping relationship between theR GB filter′s gray level and no color filter′s gray level is established,which can realize digital filtering of the n o RGB filter′s gray level,to achieve the error correction of spectr al bandwidth response.Through this method,the maximum temperature error is deeply reduced to 38.6℃ in measuring range,and the temperature measuring range is enlarged by about 300℃.The experiment results show that the method,which is based on RGB digi tal filtering to realize the calibration of color-CCD,is quite simple,practical,but high accuracy,and can largely impro ve the temperature range.