The invention provides an alignment method for a liquid crystal display device and an optical alignment device. The alignment method comprises the following steps: rotating the liquid crystal displaydevice; irradiating the liquid crystal display device with a light source in order that liquid crystal molecules in the liquid crystal display device are subjected to optical alignment. The liquid crystal display device is rotated, and the liquid crystal display device is irradiated with the light source, so that the liquid crystal molecules in the liquid crystal display device are subjected to optical alignment. When the liquid crystal display device is rotated, the light source can perform alignment of 360 degrees on the liquid crystal molecules in the liquid crystal display device, so thata preset dip angle of 360 degrees can be realized for the liquid crystal molecules, and the liquid crystal molecules can twist and incline by 360 degrees when the aligned liquid crystal display deviceis electrified. The liquid crystal molecules can twist and incline towards different directions, the alignment directions of the liquid crystal molecules are increased, the problem of color cast of the liquid crystal display device under the condition of displaying at a wide viewing angle is solved, and the viewing angle of a liquid crystal display screen is increased.