Due to the local variations of the electric-field vector caused by a single gold nanoparticle in the near-field, a new method of detecting near-field polarization states is proposed. A gold nanoparticle array with a radius of 50 nm is designed to detect the electric-field vector of different polarization. The gold nanoparticle causes local changes of the electric field vector and produces certain intensity patterns to detect the electric vectors of different polarization states. In this paper, the measurement results of five different polarization states have been mapped by FDTD, which can be distinguished visually and also relative to the different polarization properties.