In this paper, the morphology of copper hydroxide nano/microcrystals is finely controlled by adjusting the concentration of surfactant and NH 4 Cl 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 NH 4 Cl 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 H 2 O 2 . 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.