Abstract: A Monte Carlo Code MCNP5 is used to analyse the energy deposition ratio and power distribution in thorium-based molten salt experiment reactor with solid fuel (TMSR-SF1). Since MCNP5 could not deal with the deposition energy from delayed beta and gamma ray photons, an analog equivalent method is used to take them into account. Then, the energy deposition rate and power distribution in TMSR-SF1 are calculated during the beginning, the middle and the end of the reactor life cycle. The results indicate that, compared with the PWR fuel rod (which is about 95%-97%), the energy deposition ratio in the pebble of TMSR-SF1 is smaller (about 93%). At the same time, TMSR-SF1 behaves good safety feature due to its low power peak factor (about 1.5).