Three-dimensional superresolution diffractive optical elements (DOE) are designed for incidences of radially polarized light. The analysis of focusing properties of the radially polarized beam in the high numerical aperture focusing system shows that the longitudinal component of the focused radially polarized light dominates the three-dimensional intensity distribution of main lobe. Based on the global optimization method, three-dimensional superresolution DOE for the linearly polarized beam with 0 and π binary phase distribution are designed by linear programming method. Three-dimensional superresolution performances are calculated considering both transverse and longitudinal components of the focused radially polarized light. Although the optimized DOE may not be globally optimal for the radially polarized light, simulation results show that the radially polarized beam can realize better superresolution performances than the linearly polarized light, which also validates the optimization method for three-dimensional superresolution DOE considering only the longitudinal component of the focused radially polarized beam.