A simple and convenient method for the preparation of needle-shape nanoparticles of β-Ni(OH)2 has been developed. Results show that a needle-shaped β-Ni(OH)2 can be easily obtained in the presence of ethylenediamine and sodium dodecylbenzene sulfonate within a size from 100 to 200 nm. The shape and structure of the product were characterized by XRD, TEM and FT-IR. It is noteworthy that the formation of needle-shape β-Ni(OH)2 benefits from the addition of sodium dodecylbenzene sulfonate. The optimum preparation conditions and the possible mechanism are also discussed.