To solve the problem wherein the structure of a two-dimensional (2D) grating is single and does not match the actual structure, a 2D metal-medium grating is proposed that has excellent polarization independence and high diffraction efficiency and wherein the grating structure is more consistent with the actual topography. Based on the intensity distribution of a two-beam orthogonal exposure single-period interference field, a 2D grating structure based on a light intensity profile is constructed, and the grating is optimized using a Fourier mode method and particle swarm optimization algorithm. Results show that, under optimal parameters, the transverse electric and transverse magnetic polarized light diffraction efficiencies are greater than 95% when the designed 2D grating is incident at the Littrow angle at a 780-nm wavelength, and it exhibits excellent polarization independence and large preparation tolerance. In addition, a comparison of the diffraction efficiencies of traditional round and prism gratings with the same structural parameters reveal that a small change in the grating structure significantly affects the diffraction efficiency of the 2D grating. Finally, the designed structure based on a light intensity profile can effectively improve the matching degree between the design and actual grating. This research provides a theoretical basis for the development of high precision 2D grating in the displacement measurement field.