Abstract: A large amount of radioactive materials from nuclear power station were released in Fukushima nuclear accident, leading to huge damage on the human health neighbor to the station. Simulating the dispersion of the radionuclide in the atmosphere is significant for decision makers to take steps to control the pollution. A Lagrangian particle tracking method was vividly created to simulate the atmospheric dispersion of radionuclide around the world, and the result was compared with HotSpot’s result. The results show the concentrations calculated by the two models are similarity, however, the concentrations calculated by Lagrangian particle tracking method change more quickly than HotSpot’s results, fit the truth better. The Lagrangian particle tracking method can simulate the diffusion process of the nuclear power station accident, and the result of simulation can provide more actual information for early emergency and consequence assessment.