Phase flicker in liquid crystal on silicon (LCoS) devices can decrease the effective phase modulation resolution by introducing overlapped phase oscillations between adjacent modulated gray levels, thus degrading the performance of LCoS devices in various applications. However, the effect of phase flicker on a holographic display is often overlooked. From an application angle, this paper investigates the quality of the holographic reconstructed image, especially sharpness, under the static and dynamic effects of different flicker magnitudes. Both the simulation and experimental results reveal that the increment in the magnitude of phase flicker causes an equal sharpness deterioration with the reduction of the numbers of hologram phase modulation levels.