After analyzing the heat transfer of the stratospheric airship gondola and the environment at the high altitude, we propose an open carbon dioxide refrigeration system combined with cold plate. The proposed approach can avoid the insufficient cooling caused by the only use cold plate. Meanwhile, by establishing the thermal simulation model and using VC++ software, the required mass of CO₂ is obtained. Additionally, we analyse the state of CO₂ in gas tanks and the factors affecting the loss of cooling capacity during rising process. Results indicate that the calculated mass of CO₂ meets the cooling requirements for the airship rising process, and in the case of low temperature, large pipe diameter and low backpressure, the cooling capacity loss is smaller. Our research provides technical references for the cooling of electronic devices in the stratospheric airship gondola.