Nanosized cathode material Ni(OH)2 for alkaline batteries was prepared by converting the precursor of NiC2O4·2H2O in KOH water solution which contained Tween-80, and the precursor was obtained via the reaction between Ni(NO3)2·6H2O and H2C2O4·2H2O in ethanol solvent. The products were characterized using X-ray diffraction (XRD), infrared absorption spectroscopy (IR), and transmission electron microscopy (TEM). The results showed that the as-prepared Ni(OH)2 sample by this method is β(II)-type phase and its shape is spherical with the particle size from 5 to 35nm. The electrochemical studies revealed that the 10% addition of nanosized Ni(OH)2 to common microsized spherical Ni(OH)2 can improve the electrochemical performance of the Ni(OH)2 electrode. There exists approximately a 10% improvement in the utilization of the active material of the Ni(OH)2 electrode with 10% nannosized Ni(OH)2 addition in comparison with microsized spherical Ni(OH)2 electrode. Nanosized Ni(OH)2 may be a promising cathodic active material for alkaline rechargeable batteries.