Aiming at the change of cladding brittleness of high burnup spent fuel under dry transportation condition, the work aims to discuss the influence and consideration of ''keeping the assembly structure intact'' as the design basis in current spent fuel transportation and container safety research in China. Based on the mechanism of ductile-brittle transition of zircon cladding, the work analyzed the performance changes of spent fuel in off pile and transportation, and discussed the structural and performance changes of spent fuel cladding with high burnup under accident load according to the criteria proposed in ''ISG-11'' and other technical guidelines of the United States. It was generally considered that 2G spent fuel did not need to consider the impact of hydrogen embrittlement of its material; while 3G spent fuel with high burnup must be evaluated according to the influence of various factors during the process of spent fuel leaving the reactor and subsequent dry transportation. It can be judged whether the peak temperature, ductile brittle transition temperature and temperature change range of the cladding would affect the design basis of keeping the structure intact under accident conditions. As China enters the period of large amount of high burnup spent fuel transportation, the influence of hydrogen embrittlement characteristics of cladding materials under accident load on the structural retention capacity of spent fuel must be fully considered in design and transportation safety analysis of spent fuel transportation containers. It is hoped that the conclusion of the work can provide some reference and impetus to the research on the design of spent fuel transport container and the analysis of transport accidents in China.