To control the depolarization of incident laser with different polarization states, a liquid crystal depolarizer with random phase distribution structure is designed. For cholesteric liquid crystal device, a model of laser transmission through cholesteric liquid crystal device is established by using finite-difference time-domain method. The theoretical model is verified by experiments, and the polarization change and polarization distribution characteristics of laser through the liquid crystal array unit are analyzed. The simulation results show that the cholesteric liquid crystal device can achieve good depolarization effect for the linear polarized light with different polarization angles under the conditions of suitable liquid crystal material and maximum thickness of the micro-etching pit, and the applicable spectrum is wide.