Stimulated emission depletion microscopy (STED) is a powerful far-field technique for super-resolution optical imaging with a few tens even a few of nanometer spatial resolution, thus it is extensively used in investigation of cell biology and so on. The spatial resolution of STED highly depends on the intensity distribution of the doughnut-shaped depletion spot, near the objective focus. The polarization state of field has influence on focal intensity focused with high numerical aperture objective. The off-axis aberrations of microscopic system bring serious damage to the central symmetry of doughnut-shaped depletion spot. The influences of different polarization states of incidence vortex beam and aberrations of coma and astigmatism is of the optical system on the intensity profiles of doughnut-shaped depletion spot simulated by using the vectorial diffraction theory. In the experiment, the deformed depletion spot is optimized by utilizing a pure phase spatial light modulator to correct the aberrations of the optical system. A fluorescent nanoparticle is used as a probe to scan the focal region to obtain a high spatial resolution of intensity distribution. The measured results are in good agreement with those predicted by the vectorial diffraction theory.