Cuprous oxide (Cu2O) crystals with polymorphology have been synthesized under EDTA-assisted hydrothermal conditions. It was found that the branching degree of Cu2O cubes can be kinetically controlled by different reaction times, which can evolve into five typical polyhedra by selecting different reagent amounts and pH values. On the basis of chemical bonding viewpoint, a kinetic model has been proposed to explain the polymorphology formation of Cu2O crystals. Our calculated results indicate that octahedron is the thermodynamic shape of Cu2O crystal, while these five typical shapes can be kinetically simulated. Furthermore, the current kinetic model can be used to understand the growth mechanism of other inorganic crystals grown in the presence of additives. (c) 2008 Elsevier B.V. All rights reserved.