The present invention discloses a liquid crystal grating, a manufacturing method and a drive method thereof, and an optical phased array. In the liquid crystal grating, plurality of first electrodes are formed on a lower substrate with first gaps formed between adjacent first electrodes, second electrodes are further provided above the first gaps with second gaps formed between adjacent second electrodes, and an insulation layer is provided between the first electrodes and the second electrodes. When voltages are applied to the first electrodes and the second electrodes, continuously and smoothly changing electric field is generated inside the liquid crystal grating, and then phases of incident light may be controlled continuously and smoothly, which improves the ability of the liquid crystal grating to modulate light beam.