Degradation of liquid crystal cell under a blue-violet laser beam irradiation has been investigated for an evaluation of a LC cell photostability. The laser beam was focused on the LC layer in the cell. A far field pattern (FFP) was caused by the change of the LC alignment at the focused point after a few minutes irradiation. The FFP changed as a progress of the alignment degradation and it depended on LC materials, polymer materials and their combinations.