With　increasing　scale　of　offshore　wind　turbine　design　in　recent　years,　the　problem　of　rain　erosion　failure　at　leading　edge　of　blades　has　become　increasingly　prominent,　it　not　only　affects　wind　energy　conversion　efficiency　of　a　wind　turbine　unit,　but　also　poses　a　potential　threat　to　its　stable　operation.　Here,　the　smooth　particle　hydrodynamics　(SPH)　was　used　to　study　constitutive　relation　inside　raindrops,　and　the　representative　volume　element　(RVE)　model　of　a　blade　leading　edge　was　established　with　finite　element　method　(FEM).　SPH-FEM　coupled　model　was　built　to　study　the　formed　raindrop　impact　response　process　on　blade　surface.　Considering　actual　working　conditions　of　natural　rainfall,　a　raindrop　size　model　related　to　rainfall　intensity　and　a　spatial　distribution　model　of　raindrops　were　built.　By　simulating　a　single　raindrop　impact,　impact　load　on　blade　surface　and　velocity　distribution　inside　a　raindrop　were　studied　to　clarify　the　physical　process　of　raindrop　impact.　Through　analyzing　stress　and　strain　fields　caused　by　impact,　potential　damage　areas　were　evaluated.　The　simulation　model　for　multi-raindrop　impacts　was　built　to　study　coupling　actions　among　impact　stress　fields　and　the　cumulative　effect　of　plastic　strains　on　coating　surface.　The　study　results　showed　that　water　hammer　impact　is　the　key　factor　to　cause　accumulation　of　plastic　strain;　although　stress　response　amplitude　in　lateral　spraying　stage　is　small　and　exhibits　a　certain　disordered　feature,　if　there　is　a　multi-raindrop　coupled　impact,　stress　peaks　can　appear　in　the　coupled　zone　and　have　a　potential　impact　on　blade　deformation　and　failure.　©　2024　Chinese　Vibration　Engineering　Society.　All　rights　reserved.