Chemical doping of nickel hydroxide with other cations(e.g. Al~(3+)) is an efficient way to enhance its electrochemical capacitive performances. Herein, a simple cation–anion(Ni~(2+)and AlO_2) double hydrolysis method was developed toward the synthesis of nickel–aluminum(Ni–Al) composite hydroxides. The obtained composite hydroxides possesses a porous structure, large surface area(121 m~2/g) and homogeneous element distribution. The electrochemical test shows that the obtained composite hydroxides exhibits a superior supercapacitive performances(specific capacitance of 1670F/g and rate capability of 87% from 0.5 A/g to 20 A/g) to doping-free nickel hydroxide(specific capacitance of 1227 F/g and rate capability of 47% from 0.5 A/g to 20 A/g). Moreover, the galvanostatic charge/discharge test displays that after 2000 cycles at large current density of 10 A/g, the composite hydroxides achieves a high capacitance retention of 98%, indicative of an excellent electrochemical cycleability. Chemical doping of nickel hydroxide with other cations (eg Al ~ (3+)) is an efficient way to enhance its electrochemical capacitive performances. Herein, a simple cation-anion (Ni ~ (2+) and AlO_2) double hydrolysis method was developed The synthesis of nickel-aluminum (Ni-Al) composite hydroxides. The obtained composite hydroxides possesses a porous structure with a large surface area (121 m ~ 2 / g) a specific supercapacitive performances (specific capacitance of 1270 F / g and rate capability of 87% from 0.5 A / g to 20 A / g) to doping-free nickel hydroxide A / g to 20 A / g). In addition, the galvanostatic charge / discharge test displays that after 2000 cycles at large current density of 10 A / g, the composite hydroxides achieves a high capacitance retention of 98%, indicative of an excellent electrochemical cycleabili ty.