In　this　paper,　the　transition　from　Cassie　state　to　Wenzel　state　of　water　film　at　a　hydrophobic　surface　with　a　nano-groove　under　the　external　electric　field　was　studied　by　using　molecular　dynamics　(MD)　simulation　method.　It　is　found　that　there　exists　an　optimal　electric　field　strength,　at　which　the　transition　of　the　wetting　state　can　be　promoted.　For　lower　or　higher　electric　field　strength,　it　needs　a　longer　time　for　the　transition　of　the　wetting　state.　Based　on　the　calculation　of　the　droplet　contact　angle　under　the　electric　field,　it　is　found　that　the　external　electric　field　can　enhance　the　surface　wettability,　which　in　turn　facilitates　the　transition　from　the　Cassie　state　to　the　Wenzel　state.　On　the　other　hand,　the　elongation　of　the　droplet　along　the　electric　field　direction　under　the　influence　of　the　electric　field　polarization　slows　down　the　infiltration　of　the　droplet　into　the　nano-groove.　Therefore,　with　the　increase　of　electric　field　intensity,　the　transition　time　of　liquid　film　wetting　state　shows　a　tendency　of　decreasing　and　then　increasing　after　a　minimum　value.　This　paper　reveals　the　mechanism　of　the　transition　of　the　wetting　state　on　the　surface　of　nanostructures　under　the　influence　of　the　external　electric　field,　which　contributes　to　a　deeper　understanding　of　the　electrical　wetting　phenomenon　on　the　surface　with　microstructures　and　nanostructures.　©　2024　Beijing　University　of　Technology.　All　rights　reserved.