Abstract: The profiles of spectral pass bands' limb radiance by SABER(Sounding of the Atmosphere using Broadband Emission Radiometry) were simulated in the bands of 15m and 4.3m emission for CO2 by using the updated software of SHARC, and the simulated results were compared with corresponding SABER measurements to analyze the CO2 non-LTE radiative transfer properties and to validate the model. The comparisons show that SHARC can simulate the middle latitude atmosphere condition's CO2 limb radiation with a reasonable accuracy for applications. However, for some special atmosphere conditions, such as Arctic summer's atmosphere, the model has some deviations because of its algorithm's shortcoming. It is expected to improve the algorithm to contain more sophisticated chemical-kinetic processes and achieve better middle and upper atmospheric parameters, which make more accurate simulation of non-LTE radiative transfer properties.