A laser crystallization device includes a first light source providing a first light and a second light source providing a second light. The device further includes a first lens set receiving the first light to generate a first transmitted light, the first transmitted light having a first profile, the first profile having a first profile error portion and a first non-error portion. The device further includes a second lens set receiving the second light to generate a second transmitted light, the second transmitted light having a second profile, the second profile having a second profile error portion and a second non-error portion, the second profile error portion corresponding to the first non-error portion, the second non-error portion corresponding to the first profile error portion. The device further includes an optical system combining the first transmitted light with the second transmitted light.