After the spent fuel is loaded into the storage container, the drying and dehumidification procedure must be performed and the helium gas should be backfilled to build an inert gas environment, to prevent the performance degradation of the fuel cladding and container, so the work aims to discuss the key issues related to the drying technology of the spent fuel storage container. The drying criteria of the container were determined through standard research, the residual water quantity was estimated according to the two categories of the unbound water and the bound water, and the effect of the residual water and its decomposition products on the storage and transport safety was studied, and the characteristics of vacuum drying and forced helium circulating drying systems were analyzed. In the drying process, the container must follow the cladding temperature limit and dryness criteria. The residual water existed in both unbound and bound states, and the estimated residual value was about 50 mL and 18 mL to 1.8 L respectively. Residual water might affect the safety of storage and transport of spent fuel through mechanisms such as cladding oxidation, fuel pellet oxidation, cladding hydrogen absorption, combustible gas generation and aqueous corrosion. The drying efficiency of the vacuum drying system was limited due to the icing and thermal safety problems. The forced helium cycle drying system eliminated the possibility of ice formation in the container and pipeline, and kept the spent fuel at a low temperature by forced convective heat transfer. The forced helium cycle drying system can shorten the drying time, reduce the occupational radiation dose, reliably guarantee the safety of fuel heat, and have more advantages in the storage and transport scenario of high burning fuel.