This　paper　establishes　a　monopile　foundation　model　for　offshore　wind　turbines　using　the　finite　element　Software　ABAQUS,　combined　with　the　USEFLD　subroutine　to　calculate　soil　degradation,　and　uses　a　simplified　spring　model　to　ealeulate　the　natural　frequeney　of　the　monopile　wind　turbine　System.　The　effects　of　the　number　of　cyclic　load　cycles,　the　magnitude　of　cyclic　load,　and　the　size　of　the　monopile　on　the　natural　frequeney　of　the　wind　turbine　System　are　diseussed.　The　research　results　show　that　the　natural　frequeney　of　the　monopile　foundation　wind　turbine　System　decreases　with　the　increase　in　the　number　of　cyclic　load　cycles.　Moreover,　the　greater　the　cyclic　load　level,　the　more　significant　the　degradation　of　the　wind　turbine　System＇　s　natural　frequeney.　For　the　wind　turbine　size　and　soil　conditions　considered　in　this　study,　after　107　cycles　of　cyclic　loading,　the　wind　turbine＇s　natural　frequeney　can　decrease　to　as　low　as　0.954　times　its　initial　value,　but　it　still　remains　within　the　1P　to　3P　frequeney　ränge.　Increasing　the　monopile　length,　diameter,　and　wall　thickness　can　reduce　the　long-term　degradation　of　the　monopile　wind　turbine　System＇s　natural　frequeney.　Under　the　condition　of　the　same　steel　usage,　increasing　the　pile　diameter　is　more　effective　in　mitigating　the　natural　frequeney　degradation　of　the　wind　turbine　System　compared　to　increasing　the　pile　length　and　wall　thickness,　thus　ensuring　the　stable　Operation　of　the　wind　turbine　System.　＇　©　2025　Science　Press.　All　rights　reserved.