This study is focused on degradation of Direct Black dye, a common azo dye, catalyzed by nickel hydroxide in aqueous solution. Nickel sulfatehexahydrate, sodium hydroxide and sodium hypochlorite were used for synthesis of nickel hydroxide catalyst. The catalytic performance of nickel hydroxide for oxidative degradation of Direct Black dye was examined in terms of discrete parameters like effect of temperature, concentration of dye, stirring speed, time of reaction etc. Curve Expert software was used for kinetics analysis of batch experimental data. Degradation reaction was taking place according to Langmuir-Hinshelwood mechanism. According to this mechanism the reactants react in adsorbed form at the surface of nickel hydroxide catalyst.