In　order　to　comply　with　the　development　and　sustainable　development　of　islands　and　reefs　in　the　South　China　Sea,　in　view　of　the　large　air　conditioning　load　in　the　buildings　and　the　poor　energy-saving　effect　of　traditionalenvelope　structure　in　the　region,　this　paper　proposes　to　apply　the　phase　change　roof　to　the　region,　and　uses　the　wind　tunnel　test　to　explore　its　heat　transfer　characteristics　under　different　radiation　intensities,　phase　change　layer　thicknesses　and　horizontal　wind　speeds,　and　then,　combined　with　Matlab　simulation　to　further　determine　the　application　form,　thickness　and　phase　transition　temperature　of　the　phase　change　layer　suitable　for　this　area.　The　results　show　that　increasing　the　radiation　intensity　can　increase　the　temperature　rise　rate　of　the　outer　surface　of　the　roof　phase　change　layer　at　the　initial　stage　of　melting　and　solidification,　and　increasing　the　thickness　of　phase　change　layer　and　wind　speed　can　significantly　increase　the　delay　time,　but　the　effect　of　wind　speed　on　heat　transfer　attenuation　is　not　obvious.　When　the　thickness　of　the　phase　change　layer　increases　from　0　mm　to　40　mm,　the　heat　transfer　delay　time　at　each　wind　speed　increases　by　an　average　of　1.6　h.　When　the　wind　speed　increases　from　natural　convection　to　3　m/s,　the　heat　transfer　delay　time　of　the　roof　decreases　by　an　average　of　0.7　h.When　the　phase　change　layer　is　on　the　outdoor　side,　it　can　better　reduce　the　internal　and　external　surface　temperature　and　increase　the　heat　transfer　attenuation　of　the　roof.　Compared　with　the　phase　change　layer　on　the　indoor　side,　the　heat　transfer　attenuation　is　increased　by　1.1　times,　and　the　peak　temperature　of　the　inner　surface　is　reduced　by　1.6　℃;　the　thickness　of　the　phase　change　layer　should　not　exceed　30　mm;　when　the　phase　change　temperature　range　is　34~36　℃,　the　heat　transfer　attenuation　is　the　largest,　which　is　4.73,　and　the　heat　insulation　effect　is　the　best.　©　2021,　Editorial　Office　of　Journal　of　Xi＇an　University　of　Architecture　&　Technology.　All　right　reserved.