A space-borne differential absorption spectrometer is a high precision aerospace optical remote sensor. Hyperspectral, high spatial resolution spectral information can be obtained by passive DOAS technology. The temperature of device has a greater impact on the instrument measurement accuracy. It leads to severe temperature target. Due to complex and compact structure, it is hard for the instrument’s heat dissipation. To meet the temperature requirement, a thermal control scheme is presented by comprehensively analyzing the structure and power distribution feature as well as the space heat flux at sun-synchronous orbit. Thermal analysis tool I-DEAS/TMG is utilized to compute temperature distribution and fluctuations in several typical operating conditions. The heat balance experiment has been carried out to verify the thermal design. Furthermore, comparison of the simulation results and experimental data indicates that the device temperature is under control and within the preferred range.