Plate-like ZnO with good crystallinity were prepared by a simple hydrothermal synthesis method in Zn(NO3)2·6H2O and NaOH solution at 180°C. The dimension of ZnO powder ranged from 200 to 500nm and the average thickness was about 50nm. The electrochemical performances of ZnO nanoplates as anode active materials for Ni/Zn cells were investigated by galvanostatic charge/discharge cycling and cyclic voltammogram (CV). The ZnO nanoplates showed better cycle stability than the conventional ZnO, and the discharge capacity maintained 420mAhg−1 throughout 80 cycling tests. At the same time, they also exhibited higher midpoint discharge voltage and lower midpoint charge voltage. The continual SEM examinations on the electrode found that the morphology of the plate-like ZnO active material did not change essentially and the zinc dendrite was suppressed effectively, which resulted in the improvement of cycle stability of Ni/Zn secondary cells.