The work aims to ensure the safety of low enriched Uranium Hexafluoride (UF6) transport container UX-30/30B for railway transportation in summer. National and international regulations and standards as well as the material nature of the container were analyzed. Abaqus, large-scale finite element analysis software developed by Dassault Company was used to conduct thermal analysis on different working conditions to evaluate the effects of high temperature on transportation safety. –40-38 ℃ certificate referred to the ambient temperature of the atmosphere, not the temperature inside the closed carriages; 70 ℃ was within the design temperature range of the main materials of the uranium hexafluoride transport packaging and had few effects on the container performance. The package could be safely transported in a closed carriage at 70 ℃ for 24 h when transported in China's railway network; After 10 d of transportation in the case of initial temperature of 38 ℃ in the transportation container as well as the temperature in the carriage of 70 ℃ for 8 h every day, the maximum average temperature of uranium hexafluoride in the transport container was 49.66 ℃, which could meet the requirements of safe transportation at altitudes lower than 3 141 m. To sum up, low enriched uranium hexafluoride transport containers UX-30/30B are safe for railway transportation in summer.