Abstract: Two kinds of layout of condenser pipes in deployable radiator of spacecraft are compared and analyzed. Calculation and analysis of flow/heat transfer of two-phase working fluid in a parallel-style condenser are performed under microgravity conditions with SINDA/FLUINT code. It is found that the throttling pipes behind condenser have great effect on the position of vapor/Iiquid interface in condenser pipes, which provides a reference for condenser design and improvement of radiator performance.