The non-mechanical laser beam scanning system has advantages such as small size, light weight, and easy integration, and has great application prospects in fields such as LIDAR, laser weapons, and laser communication. Its aperture determines the working distance, scanning accuracy, and target destruction ability of the equipment. A fully electrically controlled large aperture laser beam scanning system based on a liquid crystal polarization grating was designed. Based on a liquid crystal polarization grating assosiated with a liquid crystal spatial light modulator, the large-angle continuous scanning of the beam was achieved. A beam scanning system and focused on analyzing the control strategy of cascaded liquid crystal polarization grating groups was designed, providing specific control methods. Finally, a preliminary scanning experiment of the laser beam was conducted, achieving a deflection of the 70 mm aperture beam at ?16.575°~16.575°. The research results provide technical support for the non-mechanical scanning control of laser beams, and make preliminary exploration in the application of large-aperture laser scanning systems.