The work aims to confirm that the STC transport cask can be used to transport multiple small assemblies through drop analysis. A transport inner liner that can load multiple small assemblies was designed. The inner liner and new fuel assemblies were compared from the dimensions of external size, weight, installation method, and center of gravity position to clarify the drop posture of the STC cask when transporting multiple small assemblies, which was consistent with that of transporting new fuel assemblies. Finally, drop analysis of the STC transport cask when loading two types of assemblies was compared. The drop analysis showed that the deformation of the STC cask when transporting multiple small assemblies was smaller than that of transporting new fuel assemblies under various working conditions. Through content comparison and drop analysis, it is proved that the STC cask can not only be used to transport new fuel assemblies, but can also be reused to transport multiple small assemblies. This transportation scheme meets the drop acceptance standards, ensures the closed state of the cask during drops under various working conditions, improves design efficiency, and saves development costs.