Nano-sized nickel hydroxide particles were synthesized at room temperature by a facile coordination precipitation method, through simply dropping sodium hydroxide solution to dissociate the complex of nickel-hexammonia, using nickel chloride, ammonia and sodium hydroxide as raw materials. Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetry and derivative thermo-gravimetry (TG-DTG), X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were used to characterize the products. It is demonstrated that the product is pure β-type nickel hydroxide, which contains more nickel and fewer intercalated anions comparatively, and likely boosts its electrochemical activity. The average size of β-type nickel hydroxide nano-particles is about 100 nm