Abstract: To investigate the influence of the radiation heat transfer on cryogenic target system, a computational fluid dynamics model for cryogenic target with a radiation shield is established. The modeling is implemented with FLUENT software, and the discrete ordinates model is adopted for calculating radiation heat transfer. The structure and parameters participating in radiation heat transfer are analyzed. The results show that the following measures help to reduce the radiation heat transfer and improve the temperature unity around the target: using double radiation shield, decreasing the emissivity of the radiation shield, increasing the diffusion fraction of the radiation shield, increasing the absorptivity of the hohlraum, and adding storm windows.