This communication demonstrates a novel strategy for the selective growth of Au nanograins (AuNGs) on specific positions (tips, edges and facets) of Cu(2)O octahedrons to form Cu(2)O-Au hierarchical heterostructures. The surface energy distribution of the octahedrons generally follows the order of γ((facets)) < γ((edges)) < γ((tips)) and leads to the preferential growth and evolution of the heterostructures. These novel Cu(2)O-Au hierarchical heterostructures show fascinating degradations of methylene blue (MB), due to the suppressed electron/hole recombination phenomena and the highly efficient light harvesting.