Abstract: With the intensification of environmental air pollution degree, especially CO2 increasing, various countries pay more and more attention to monitoring of atmospheric environmental quality. High spectral and high resolution CO2 detector are corresponding got more and more attention. But the satellite-borne detector must satisfy the space environment to ensure imaging quality. Mounting seat as the key components of the detector, its design is reasonable or not, has a great influence on the precision of detector. Thus, three kinds of mounting seat structure were designed according to the requirements of the detector use and installation interface. The structure properties were compared in mechanical vibration environment and temperature increasing. The results derived from theory and experiment. The results show the first-order frequency of mounting seat can reach 82 Hz, the deflection between collimating mirror components and grating surface is less than 10, the deflection between imaging lens components and grating surface is less than 10. These results can meet design technical requirement. The effect of translational mounting seat structure relative to collimation mirror components and imaging lens components is the smallest. The results are less than 17 to ensure the imaging quality of detector in 4℃ temperature environment. The structure is reasonable and feasible. The structure can provide reference for support design of relative instrument latterly.