In this paper, the morphology of copper hydroxide nano/microcrystals is finely controlled by adjusting the concentration of surfactant and NH4Cl as well as the reaction temperature, to provide plates, belts, wires, rods and urchin-like spheres, among others. A tree-type multiple head surfactant, bis (amidoethyl-carbamoylethyl) octadecylamine (C18N3), was used to prepare the copper hydroxide nano/microcrystals and it acted as a face-selective additive in the reaction system. The morphology of the Cu(OH)(2) microcrystals could be transformed from elliptical plates into truncated square plates as the NH4Cl concentration was increased. The results showed that the Cu(OH)(2) crystals were better than the amorphous type of Cu(OH)(2) in catalyzing the oxidation of resorcinol with H2O2. Additionally, an investigation of the formation process of the nano/microcrystals was performed, which we believe is valuable for a precise understanding of the formation and fabrication of other metal hydroxides and metal oxides. (C) 2010 Elsevier Inc. All rights reserved.