In the light of the payload cooling requirements of space-based infrared staring and scanning observation systems, pump driving circuits having advantages of strong fluid and heat transferring, high-lift and high adjustability can be used as the cooling circuits for long distance large area array distribution payloads. It is very important to control the gas void fraction in a single phase liquid circuit. A gas-liquid separation device based on the flow mechanism of two phase fluid in a porous zone is designed. Its design ideas and test verification are presented. Optimized parameters are obtained through numerical calculation and simulation. Flow parameters are measured. The gas-liquid separation effectiveness of this device is verified.