Vanadium　dioxide　(VO2)　is　well　known　for　its　metal-insulator　transition　(MIT)　at　341　K.　Normally,　the　VO2　presents　a　metallic　rutile　(R)　phase　above　the　T-c,　but　an　insulator　(monoclinic,　M)　phase　below　the　T-c.　Besides　the　thermally　driven　mode,　the　phase　transition　can　also　be　triggered　electrically,　which　is　common　in　electron　devices　like　field　effect　transistors　and　actuators.　Due　to　the　electron　correlation,　the　Mott　transition　associated　with　electronelectron　interaction　as　well　as　the　Peierls　transition　involving　electron-lattice　interaction　are　both　believed　to　drive　the　transition　of　VO2,　although　the　actual　MIT　mechanism　is　still　under　debate　in　condensed　matter　physics.　The　Coulomb　screening　of　the　electron　hopping　can　be　broken　by　injecting　enough　carriers.　However,　the　issue　is　more　complicated　in　the　electrically-triggered　MIT　of　VO2　due　to　the　Joule　heat　of　current　and　the　carrier　injection　of　field　effect.　In　this　work,　we　study　the　electrically　induced　MIT　in　VO2　nanowires　by　in-situ　transmission　electron　microscopy　(TEM).　We　build　a　closed　circuit　under　the　TEM　by　using　in-situ　electric　TEM　holder　to　capture　the　changes　of　VO2　in　electron　structure　and　phase　structure　simultaneously.　An　alternating　bias　voltage　is　applied　to　the　VO2　nanowire　while　the　selected　area　electron　diffraction　(SAED)　patterns　of　VO2　nanowire　are　recorded　using　Gatan　Oneview　(R)　fast　camera.　The　current　rises　or　drops　suddenly　in　the　current-voltage　curve　(I-V　curve),　indicating　a　phase　transition,　through　which　the　SAED　pattern　of　nanowire　is　recoded　every　5　ms.　By　correspondence　analysis　between　the　SAED　patterns　and　the　I-V　data　at　every　moment,　a　transition　state　of　insulating　R　phase　is　observed,　which　is　obviously　different　from　the　normal　state　of　the　metallic　R　phase　or　the　insulating　M　phase.　The　existence　of　the　insulating　R　phase　indicates　that　electron　structure　transforms　prior　to　the　phase　transition.　The　decoupling　phenomenon　reveals　a　predominant　role　of　electron-electron　interaction.　Moreover,　by　feedback　strategy　of　the　circuit,　the　current　through　the　metallic　nanowire　of　VO2　remains　unchanged,　and　thus　keeping　the　Joule　heating　in　the　nanowire　constant,　the　phase　transition　from　metal　to　insulator　does　not　happen　until　the　voltage　decreases　to　about　1　V.　When　phase　transition　to　insulator　happens　in　voltage　stepdown,　even　stronger　Joule　heating　is　generated　because　of　the　increased　resistance　of　VO2　nanowire.　Therefore,　the　VO2　phase　transition　is　triggered　electrically　by　the　carrier　injection　instead　of　the　Joule　heating.　The　injecting　of　enough　carriers　can　break　the　screening　effect　to　activate　the　electron　hopping　and　initiate　the　phase　transition.　The　deduction　is　confirmed　by　the　decoupling　phenomenon　in　the　insulating　R　phase.　Additionally,　the　polarized　shift　rather　than　the　phase　transition　of　the　VO2　nanowire　is　observed　in　the　non-contact　electric　field　mode,　which　also　supports　the　cause　of　the　carrier　injection　for　the　electric　induced　MIT.　The　results　prove　the　electron-correlation-driven　MIT　mechanism,　or　so　called　Mott　mechanism,　and　open　the　new　way　for　electron　microscopy　used　to　study　the　electron　correlated　MIT.