Liquid crystal phased array is a kind of electronically controlled programmable optical phased array device based on liquid crystal, which has the advantages of small size, light weight, low power consumption and easy control. The device can precisely control the beam steering by modulating the phase of the incident beam, which not only realizes the performance of fast and flexible the spatial scanning for automatically acquisition, tracking and aiming at the moving targets, but also improves the system integration, and reduces the manufacturing cost. Liquid crystal phased array can be widely used in the fields of radar and space optical communication and other fields. This paper summarizes the research progress and key technologies of liquid crystal phased array at home and abroad, mainly including beam control, system analysis and modeling, and system performance optimization. The application and research progress of liquid crystal phased array in high-energy laser, space optical communication and Lidar are also introduced.