A significant enhancement of electroluminescence (EL) efficiency from silicon nitride-based light-emitting devices (SiNx-based LEDs) is achieved by introducing a nanostructural silver layer underneath the active matrix. The efficiency droop phenomenon of the SiNx-based LEDs is improved, which is mainly originated from the enhancement of spontaneous emission rate due to the coupling between excitons and localized surface plasmons (LSPs) as well as the weakening of the Auger recombination. The stability of our devices is also improved by the addition of Ag nanostructures, where a lower turn-on voltage and a higher break-down current are achieved. EL peaks from both the devices with and without Ag nanostructures show a blue-shift (from red to yellow) with the increase of the injected current. The evolution of EL from the SiNx-based LEDs via the addition of silver nanostructures is proposed.