Rare-earth ion doped upconversion nanocrystals show wide applications in bioimaging and photovoltaics. However, its low upconversion efficiency limits their applications. The single Au nanorod and single upconversion nanocrystal are coupled in nanometer scale with an atomic force microscope probe manipulation. The effect of localized surface plasmon resonance of Au nanorod on the nanocrystal′s upconversion luminescence is studied by single-particle spectroscopy. Results show that the upconversion luminescence intensity of nanocrystal shows strong dependence on the laser polarization direction. When the laser polarization is parallel to the long axis of Au nanorod, the maximum enhancement folds of 18 and 40 are obtained for the green and red upconversion luminescence of nanocrystal.