To　make　the　dynamic　characteristics　of　ice-covered　EHV/UHV　multi-circuit　transmission　lines　on　the　same　tower　clear,　the　dynamic　response　of　ice　shedding-caused　drastic　conductor　vibration　was　analyzed　by　finite　element　method　(FEM).　Correspondingly,　considerting　the　influence　of　geometrical　nonlinearity　and　taking　the　double　circuit　1000　kV　transmission　line　and　double　circuit　500　kV　transmission　line　on　the　same　tower　as　well　as　single　circuit　±800　kV　DC　transmission　line　and　double　circuit　500　kV　transmission　line　on　the　same　tower　for　examples,　refined　numerical　analysis　models　of　ice　shedding-caused　vibration　for　conductor　(overhead　groundwire)-insulator　system　and　tower-conductor　(overhead　groundwire)-insulator　system　were　built　by　FEM,　in　which　the　factors　such　as　coupling　effect　of　tower　with　lines,　the　position　of　ice-shedding,　span　and　height　diffferences　were　taking　into　account,　and　the　analysis　on　the　systems　under　various　operating　conditions　were　completed.　Analysis　results　showed　that　when　the　tower　height　was　higher,　the　longitudinal　unbalanced　tension　of　conductor　vibration　caused　by　ice-shedding　was　slightly　influenced　by　the　coupling　effect　of　tower　with　lines,　however,　the　longitudinal　unbalanced　tension　of　ice　shedding-caused　overhead　groundwire　vibration　was　influenced　obviously;　the　ice　shedding-caused　longitudinal　unbalanced　tensions　of　the　spans　at　both　ends　of　transmission　line　were　evidently　higher　than　those　of　spans　in　the　middel　of　transmisson　line.　Based　on　analysis　results,　it　was　suggested　that　the　percentages　of　longitudinal　unbalanced　tension　of　ice　shedding-caused　vibration　of　conductor/overhead　groundwire　in　different　voltage　classes　should　taken　as　following:　for　1000　kV　and　±800　kV　conductors,　the　percentage　should　be　taken　as　10%;　for　500　kV　transmission　line,　the　percentage　should　be　taken　as　20%;　and　for　overhead　groundwire　the　percentage　should　be　taken　as　100%.