A light exposure system executing a light exposure process to a plurality of assembly cells, each of which includes a first substrate, a second substrate and a liquid crystal layer disposed between the first and second substrates, comprises: a transmission device; two moving stages disposed on the transmission device and carrying the assembly cells; and a light source module including at least a light emitting element, wherein the transmission device moves at least one of the moving stages carrying the assembly cell or the light source module, and the light emitting element emits the light to the assembly cell, wherein the assembly cells include a first assembly cell and a second assembly cell, the moving stages carry the first assembly cell and the second assembly cell, respectively, wherein when the light exposure process is executed to the first assembly cell, the second assembly cell receives the work of cell replacement and alignment, electrode contact and application of electric field, wherein when the light exposure process is executed to the second assembly cell, the first assembly cell receives the work of cell replacement and alignment, electrode contact and application of electric field. A light exposure process applied to the light exposure system is also disclosed.