Using reactive radiofrequency magnetron sputtering, ZnO films were deposited on Si (001) substrates with plused negative bias. The atomic force microscopy was used to study the morphological evolution of ZnO films. The nucleation and growth behavior of the films are quantitatively characterized with the dynamic scaling theory. It is found that the island density of ZnO films increases and the grain size decreases with the increase of deposition time. Compared with the film depositions without bias, the stage of low-rate nucleation disappears due to the application of plused negative bias. The growth exponents of the nativedefect nucleation and the ionbombardment defect nucleation are determined to be (0.45±0.03) and (0.22±0.04), respectively. With the voltage of plused negative bias increasing, the island sizes and the roughness increase and the preferred orientation of the films is changed.