A silicon crystallization system includes a beam generator generating a laser beam, first and second optical units for controlling the laser beam from the beam generator; and a stage for mounting a panel including an amorphous silicon layer to be polycrystallized by the laser beam from the optical units. The first optical unit makes the laser beam have a transverse edge and a longitudinal edge longer than the transverse edge, and the second optical unit makes the laser beam have a transverse edge and a longitudinal edge shorter than the transverse edge.