In this study, a flat-topped beam with good uniformity is obtained using a spatial light modulator and designing a phase hologram composed of a geometric mask and gratings inside and outside of the mask. Among these, the internal grating can be gradient orthogonal grating or gradient binary grating, which can diffract the incident Gaussian beam into multiple nonzero-order beam to change the energy distribution and obtain a flat-topped beam with high uniformity. At the same time, the grating methods are compared to the GS method. Although GS method can obtain high energy efficiency, the uniformity is poor, so it is not suitable for areas requiring high uniformity. The method proposed in this paper can obtain a shaping beam with steep edge and high uniformity, with an energy efficiency of 43.71% and a minimum nonuniformity of 2.12%. It can be used in areas where high uniformity and steepness edge are required, such as scribing and removing films from coating materials (thin films without harming the substrate), and grooving in semiconductor materials (such as Low-K). This method is simple and easy to use, and it will broaden the scope of laser applications in the field of material processing.