In order to realize non-mechanical large-angle beam steering, an LC optical phased array system using phase retarder and birefringent prism is studied. The simulation and analysis of beam steering result and phase distribution by liquid crystal spatial light modulator(LCSLM) is presented, using phase modulator of VirtualLab. The angle magnifier principle of half-wave LC retarder and birefingent prism is introduced. Then the parameters which impact on incidence angle and emergence angle are analyzed, to table the optimized parameter groups. The polarization of incidenceangle can be changed by altering the voltage of half-wave LC retarder, and voltage parameter groups are achieved. The experiment results confirm that phase retarder and birefringent prism are useful. In this paper, the phase retarder controlled by voltage is proved to be able to choose the path of beam, which can be widely used in the non-mechanical large-angle beam steering.