Abstract: The Prometheus project reactor was modeled as a prototype and numerical analysis using CFD software was also conducted. The power profile of the reactor core was obtained by the Monte Carlo method and the thermal-hydraulic simulation of one-sixth of the reactor was conducted by using the Star-CCM+ software. The temperature field, velocity field and pressure field were acquired and possible optimization suggestions were proposed based on the evaluation of the current model. It is shown that the coolant in the reactor design can be heated up to the design temperature and the main technology requirements can be satisfied. However, optimization is still needed in the reactor inlet and outlet region from the perspective of optimization. The direction of inlet nozzle can be changed to reduce unnecessary loss and increase the uniformity of temperature and velocity field at the outlet. Meanwhile, negative effects of the coolant on the turbine and other equipment are also reduced.