Traditional　optical　switches　relying　on　the　weak,　volatile　thermo-optic　or　electro-optic　effects　of　Si　or　SiN　waveguides　show　a　high　consumption　and　large　footprint.　In　this　paper,　we　reported　an　electric-driven　phase　change　optical　switch　consisting　of　a　Si　waveguide,　Ge2Sb2Te5　(GST)　thin　film　and　graphene　heater　suitable　for　large-scale　integration　and　high-speed　switching.　The　reversible　transition　between　the　amorphous　and　crystalline　states　was　achieved　by　applying　two　different　voltage　pulses　of　1.4　V　(SET)　and　4　V　(RESET).　The　optical　performance　of　the　proposed　switch　showed　a　high　extinction　ration　of　44-46　dB　in　a　wide　spectral　range　(1525-1575　nm),　an　effective　index　variation　of　Delta　n　(eff)　=　0.49　and　a　mode　loss　variation　of　Delta　alpha　=　15　dB　mu　m(-1)　at　the　wavelength　of　1550　nm.　In　thermal　simulations,　thanks　to　the　ultra-high　thermal　conductivity　of　graphene,　the　proposed　switch　showed　that　the　consumption　for　the　SET　process　was　only　3.528　pJ　with　a　1.4　V　pulse　of　5　ns,　while　a　4　V　pulse　of　1.5　ns　was　needed　for　RESET　process　with　a　consumption　of　1.05　nJ.　Our　work　is　helpful　to　analyze　the　thermal-conduction　phase　transition　process　of　on-chip　phase　change　optical　switches,　and　the　design　of　the　low-energy-consumption　switch　is　conducive　to　the　integrated　application　of　photonic　chips.