Due to its good water solubility, biocompatibility and reversible self-assembly property, ferritin has been widely used in the encapsulation and delivery of bioactive molecules. Benefiting from the inherent tumor-targeting feature, ferritin nanocavities loaded with drug molecules or nanoparticles can be used for cancer imaging, diagnosis and treatment. Scientists have made efforts to reconstruct ferritin nanocages to expanded the application of ferritin. In this paper, the structural characteristics of natural and manufactured ferritin molecules are summarized, and the recent progress in their application in the fields of bioactive molecule encapsulation, heavy metal detection and biomedicine is reviewed.