Gross　Ecosystem　Product　(GEP)　is　a　single　currency　to　measure　the　contribution　of　an　ecosystem　to　society.　It　is　the　sum　of　the　value　of　products　and　services　provided　by　the　ecosystem　to　humans.　Based　on　this,　GEP　characterizes　the　current　situation　of　the　ecological　environment　in　a　region　and　can　measure　the　contribution　index　provided　by　ecosystems.　Based　on　land　use　data,　rainfall　data,　soil　data,　statistical　yearbook,　DEM　and　other　data,　this　paper　constructs　the　accounting　framework　of　Hainan　Island’s　GEP,　quantitatively　evaluates　Hainan　Island’s　GEP　from　2010　to　2020　and　analyzes　the　research　results.　The　results　are　as　follows:　(1)　The　GEP　of　Hainan　Island’s　ecosystem　rose　from　596.404　billion　CNY　in　2010　to　1032.096　billion　CNY　in　2020,　an　increase　of　about　42.21%　with　an　average　annual　growth　rate　of　6.3%.　The　overall　GEP　has　shown　an　upward　trend.　Among　them,　the　value　of　regulation　service　accounts　for　the　largest　proportion　was　up　to　73–83%.　(2)　The　overall　distribution　of　GEP　in　Hainan　Island　is　uneven,　decreasing　from　the　central　mountainous　areas　to　the　eastern　coastal　areas　around　to　the　west.　In　particular,　Danzhou　City,　Wenchang　City　and　Haikou　City　have　higher　values,　while　Tunchang,　Baoting　County　and　Wuzhishan　City　have　lower　values,　and　Wuzhishan　City　has　the　lowest　values.　Hainan　Island　is　rich　in　natural　resources,　which　contain　great　value.　Through　the　accounting　of　GEP,　we　can　clearly　determine　the　value　of　the　ecosystem,　which　can　help　the　relevant　departments　estimate　the　GEP　of　Hainan　Island’s　ecosystem.　It　can　provide　a　reference　for　Hainan　to　formulate　ecological　protection　and　sustainable　development　policies,　and　for　the　GEP　estimation　of　other　islands.　©　2022　by　the　authors.