Last decade has witnessed the unique ability of localized surface plasmon resonance nanostructure to significantly enhance upconversion luminescence efficiency of lanthanide ions, which has been demonstrated in terms of either increased absorption cross section or accelerated radiative decay rate (Purcell effect) induced by the concentrated electromagnetic field. Herein, we report the upconversion luminescence enhancement of NaGdF4:Yb/Er by dual plasmonic Au-CuS heterodimer nanocrystals, where both the local field enhancement effect and Purcell effect, initialized by different parts of the heterodimer, contribute jointly to the enhancement of upconversion emissions. This work provides the possibility to implement LSPR-based enhancement of upconversion luminescence by metal-semiconductor dual plasmonic antennas, where the judicious combination of active LSPR wavelengths can be manipulated via geometrical design of hetero-nanostructure.