Abstract: The steady thermal characteristics of the new space heat pipe reactor were analyzed by applying the commercial CFD software FLUENT. According to the power distribution of core obtained by MCNP code calculation and selecting the three adjacent fuel elements with the highest power to analyze, seven normal working conditions with different control drum angles and single heat pipe failure accident condition were calculated and analyzed. The temperature distribution of each layer of the hottest fuel-heat pipe element was obtained. The temperature distribution of steam zone was calculated by the two-dimensional heat pipe analysis program and used as the temperature boundary of the three-dimensional model. The power distribution was added to the fuel by the user defined function (UDF). The results show that the heat pipe has sufficient heat transfer capacity to remove the fission power under the designed value 4.0 MW. Meanwhile, the material temperature of each layer is lower than the safety limits and has large safety margins. The core design meets the requirements.