Based on the enhanced electron–hole recombination rate generated by surface plasmon (SP) waves of Au nanoparticles (NPs) and electrons transferred from CdSe quantum dots (QDs) to Au NPs, we propose a mechanism to elucidate the luminescent behavior in Au and CdSe nanocomposites. With our proposed model, the enhancement of the spectrally integrated PL intensity can be manipulated by up to a factor of ∼33, the largest value ever reported. Our study can be used to clarify the ambiguity in controlling the light emission enhancement and quenching of semiconductor nanocrystals coupled with the SP waves of metal NPs. It should be very useful for the creation of highly efficient solid-state emitters.