Surface-plasmon (SP) enhancement of amorphous-silicon-nitride (a-SiNx) light emission with single-layer gold (Au) waveguides is experimentally demonstrated through time-resolved photoluminescence measurement. The a-SiNx active layer with strong steady-state photoluminescence at 560 nm is prepared by plasma-enhanced chemical vapor deposition, and the Au waveguide on the top of the a-SiNx layer is fabricated by magnetron sputtering. The maximum Purcell factor value of ~3 is achieved with identified SP resonance of the Au waveguide at ~530 nm.