Abstract: By reference to the calculation features of fire dynamics simulation (FDS) analysis software and the combustion mode of sodium fire, the combination of sodium fire numerical calculation model which used chemical kinetic and FDS software made this software have simulation function of sodium combustion. The experimental data of two sodium fire tests were used to verify the calculation results, including room temperature, pressure, liner temperature, and oxygen mole fraction. The results show that the calculated room temperature, liner temperature and oxygen mole fraction are in good agreement with the experimental results and in accord with the actual conditions of sodium fire, but the calculated pressure and the experimental results are very different.