Conductive　connection　of　localized　surface　plasmons　(LSPs)　was　achieved　by　depositing　a　layer　of　continuous　gold　film　onto　the　top　surface　of　a　matrix　of　randomly　distributed　gold　nanoparticles　(AuNPs)　that　were　originally　isolated　on　a　glass　substrate.　Ultrafast　spectroscopic　response　of　such　plasmonic　nanostructures　was　investigated　by　femtosecond　pump-probe　detection　technique.　The　transient-absorption　data　showed　large　redshift　and　broadening　of　the　resonance　spectrum　of　the　conductively　connected　AuNPs　with　respect　to　the　isolated　ones.　Such　effects　led　to　modulation　on　the　evolution　dynamics　of　LSPs　in　a　transient　transition　spectral　band.　Making　use　of　the　temporal　and　spectral　dislocation　between　the　edges　of　transition　band,　we　achieved　much　increased　speed　of　the　plasmonic　optical　switching　effect.