Abstract: The fuels of molten salt reactor redistribute due to the circulation of fuel and the fission products in fuel are extracted by the online fuel reprocessing unit, which all lead to the fuel management code for the conventional reactors using solid fuel not applicable. The micro-depletion fuel management code named MOREL, adopting “two steps” method, was developed in this study based on the analytic basis functions expansion nodal method and transmutation trajectory analysis (TTA) method, and some numerical tests were chosen to verify the code. The results indicate that MOREL has high precision. At last, the preliminary fuel reprocessing simulation was examined for thorium-based molten salt reactor.