Providing a fabrication method of a periodic domain inversion structure. A nonlinear optical ferroelectric material substrate is provided. A photoresist layer is formed on the upper and the lower surface of the substrate, and periodic gratings formed by interference of two laser beams are employed to expose the photoresist layer on the upper surface. Meanwhile, the two laser beams pass through the substrate, so the periodic gratings are used to expose the photoresist layer on the lower surface. A development process is performed to form a periodic photoresist pattern on the two surfaces of the substrate. A conductive layer is formed above the substrate for covering the photoresist pattern and the surface of the exposed substrate. The photoresist pattern and a portion of the conductive layer thereon are removed by lift-off. A voltage is applied to the substrate via the remaining conductive layer to polarize parts of the substrate.