In　order　to　obtain　the　influence　law　and　microscale　mechanism　of　droplet　wetting　state　in　microgravity,　the　model　of　nano-droplet　on　array　micro-structured　surface　with　different　wettability　and　gravity　was　built　and　simulated　by　molecular　dynamics.　In　conditions　of　no　gravity,　it　was　found　that　critical　point　of　wetting　state　transition　was　closer　to　weak　wettability　surface　with　the　decrease　of　low　range　micro-column　height.　What＇s　more,　the　droplet　contact　angle　increased　first　and　then　decreased　with　larger　micro-column　height　when　h*　＜　1.5.　Under　the　action　of　gravity,　the　droplet　Cassie　state　basically　did　not　appear.　The　greater　gravity　made　the　droplet　wetting　state　transition　(from　Cassie　to　Wenzel-Cassie　to　Wenzel)　need　lower　requirements　for　surface　wettability　and　micro-column　height.　Moreover,　micro-gravity　environment　was　conducive　to　droplets　transition　from　Wenzel　to　Wenzel-Cassie　or　Cassie　state,　which　promoting　droplet　drainage.　Finally,　a　simple,　effective　and　reliable　method　was　put　forward　to　judge　the　droplets　wetting　state　under　different　gravity,　with　the　aim　of　providing　a　technical　support　for　controlling　droplet　to　be　in　Wenzel-Cassie　state　under　gravity.　(C)　2021　Elsevier　Ltd.　All　rights　reserved.