This　study　used　high-resolution　remote-sensing　technology　and　CFD　models　to　carry　out　a　simulation　study　of　a　three-dimensional　(3D)　USTE　for　daytime　and　nighttime　at　a　block　scale.　Firstly,　the　influence　of　vegetation　with　different　spatial　layouts　on　the　3D　USTE　was　analyzed.　Moreover,　the　heat　transfer　process　and　heat　conduction　process　between　urban　surface　components　at　the　block　scale　were　simulated,　and　in　the　meanwhile,　the　distribution　and　changes　of　the　3D　USTE　and　the　regional　wind　pressure　environment　were　monitored.　The　simulation　results　showed　that　(1)　vegetation　has　a　relatively　significant　mitigation　effect　on　the　thermal　environment　near　the　surface,　(2)　vegetation　with　different　morphologies　and　layouts　results　in　significant　differences　in　the　mitigation　efficiency　of　wind　speed　and　canyon　USTE,　and　(3)　the　seasonal　spatial　3D　temperature　can　be　mitigated　as　well.　In　addition,　this　study　analyzed　the　mitigation　effect　of　vegetation　on　the　urban　wind-heat　environment　during　both　daytime　and　nighttime.　The　results　indicated　that　(1)　the　mitigation　effect　of　vegetation　is　more　significant　during　the　daytime,　while　showing　a　small　value　at　night　with　an　even　temperature　distribution,　and　(2)　convection　heat　transfer　is　the　primary　cause,　or　one　of　the　major　causes,　of　differences　in　the　USTE.