Porous Co3O4 with different structures have been synthesized by annealing cobalt-based metal-organic framework (Co-MOF) parallelepiped microcrystals. The transformation process of nanostructures at different temperatures has been investigated, which involves the depletion of Co-MOF core, formation, and crystal growth of cobalt oxide shell. Porous hollow parallelepipeds and microsheets can be obtained at 400 and 500 A degrees C, respectively. When evaluated as electrode materials for supercapacitors, Co3O4 hollow parallelepipeds exhibit better electrochemical performances compared to Co3O4 microsheets, which can be attributed to the unique 3D hierarchical hollow structure and small particle size.