The integration of organic and inorganic building blocks into hierarchical porous architectures makes potentially desirable catalytic material in many catalytic applications due to their combination of dissimilar components and well-constructed reactant transport path. In this study, we prepared the hierarchical porous Co3O4@graphene 3D gel by hydrothermal method to achieve high catalytic performance in PET glycolysis reaction. Obtained Co3O4@graphene 3D gel consisted of interconnected networks of Co3O4 and graphene sheets, providing large number of accessible active sites for efficient catalytic reaction. These structural merits from synergistic effect of Co3O4 and graphene gave a high performance in the PET degradation reaction giving high conversion yield of BHET, fast degradation rate of PET, and remarkable stability.