The β-Ni(OH)2 nano-scale powder with needle-like and quasi-spheroshape was prepared by supersonic-assistant precipitation method using Tween-80 (C64H124O26-80) as dispersant. The prepared powder was added into micron-scale spheroshape nickel hydroxide at a ratio of 8% to get a combination electrode. Using the combination electrode as anode and LaNi5 alloy as cathode, the effect of Tw-80 dosage on the tap density of β-Ni(OH)2 and the discharge capability of the combination Ni electrode was studied. The result showed that both the tap density and the discharge capability increased at first, then decreased as the increase of dosage of Tw-80. The combination electrodes have a higher discharge voltage than the pure spheroshape Ni(OH)2. The maximum discharged capability with 256.75 mAh/g was obtained when the nanopowder with 2% dosage of Tw-80 was mixed with pure spheroshape Ni(OH)2 at a ratio of 8%. The capacity was 11.3% higher than that of the pure spheroshape Ni(OH)2 (230.7 mAh/g). Besides, the cycle life of the mixed electrode was also increased.