A novel optical phased array based on Liquid crystal was studied, and its structure scheme feature is a planar wavegude with liquid crystal cladding. Propagation, output diffraction characteristics and other peformances of liquid crystal-optical phased array were all studied and analyzed according to Frank-Oseen continuum elastic theory and grating diffraction theory. The research results show that the electrical control phase delay of the device is quantitatively analyzed to obtain larger optical path difference; the period number of electrodes, elcetrode width, spacing of adjacent electrodes of the device are of great effect on the intensity distribution and the full width at half maximum of output diffraction beam, and the feasibility of beam scanning is also demonstrated; this novel strcture could improve the response time for an order of magnitude as well as wavelength dispertion of the device. These theoretical basis and technical design basis are favour of developing this novel liquid crystal-optical phased array in the future.