Based on the rigorous vectorial diffraction theory, the mechanism that the subwavelength gratings convert circular polarized light into linear polarized light was analyzed. Based on the analysis results, a design method of controlling polarization state of output beam with grating spatial distribution was proposed. Using this method, several subwavelength grating polarizers with annular gratings areas were designed. By changing the number of the annular gratings areas, different type of cylindrical vector beams can be obtained. Using the Richards-Wolf vectorial diffraction method, the amplitude and intensity distributions of the different components in the vicinity of focus were calculated on high numerical aperture condition. Most of the intensity distributions in the vicinity of focus were flattop distributions. The full width at half maxima of intensity is 1.541 λ in radial direction. Compared with other type of beams such as linearly polarized beam, radially polarized beam and azimuthally polarized beam, the optical performances of the output beams from the polarizers designed in this research are distinctly particular.