Excitation　using　femtosecond　laser　pulses　induced　ultrafast　heating　of　discontinuous　gold　nanowires,　resulting　in　transient　thermal　expansion　of　the　gold　nanostructures　that　constitute　the　nanowires.　The　cross-plasmon　resulting　from　the　closely　arranged　gold　nanostructures　along　the　nanowires　was　modified　by　the　change　in　the　small　gaps　due　to　the　thermal　effect.　This　led　to　the　spectral　shift　of　the　cross-plasmon　resonance　and　laid　the　photophysical　basis　for　the　optical　switching.　A　femtosecond　pump-probe　scheme　was　used　to　investigate　the　ultrafast　optical　switching　dynamics.　The　most　efficient　optical　switching　effect　was　observed　when　the　pump　and　probe　laser　pulses　were　polarized　perpendicular　and　parallel　to　the　discontinuous　gold　nanowires,　respectively.