For massive utilization of hydrogen energy, it is necessary to transport a large quantity of hydrogen by liquefied hydrogen carriers. However, the current rule on ships carrying liquefied hydrogen in bulks do not address the maritime transport of liquefied hydrogen, and the safety assessment of liquefied hydrogen carriage is thus very important. In the present study, we spilled liquefied hydrogen and LNG (Liquefied Natural Gas) on the surface of various materials, and compared the difference of their spread and dispersion. Liquefied hydrogen immediately dispersed upward compared to LNG. Furthermore, we also measured the flammability limit of low temperature hydrogen gas. Its range at low temperature was narrower than the range at normal temperature.