The　discomfort　index　(DI)　is　an　important　indicator　that　measures　the　human　heat　sensation　for　different　climate　conditions.　Currently,　DI　of　a　city　is　usually　calculated　using　data　from　a　single　or　a　few　weather　stations　and　hence　does　not　accurately　represent　various　thermal　discomfort　states　of　the　whole　city.　In　addition,　because　the　result　of　existing　DI　is　just　a　single　numeric　value,　it　does　not　reveal　the　spatial　variation　of　thermal　discomfort　levels　and　thus　is　unable　to　represent　actual　living　environment　conditions.　This　greatly　limits　the　DI　application.　Taking　Fuzhou　of　southeastern　China　as　an　example,　this　paper　proposes　a　technique　to　produce　a　fine-scale　DI　map　by　combining　a　sharpened　Landsat　thermal　infrared　image　with　in-situ　measured　meteorological　data.　The　DI　map　clearly　reveals　the　spatial　details　of　DI　in　different　locations　of　the　city.　It　provides　quantitative　characterization　of　the　living　environment　of　each　DI　level　based　on　a　3-graded　DI　map.　This　greatly　expands　the　application　range　of　the　index.　The　quantitative　analysis　results　show　that　the　area　of　high　building　density　substantially　increases　outdoor　human　thermal　discomfort　sensation,　while　high　vegetation　and　water　covers　reduce　the　discomfort　sensation.　The　impact　of　built　surface　to　human　discomfort　sensation　is　near　two　times　more　than　those　of　vegetation　and　water　in　the　Fuzhou　case.　©　2017　Elsevier　B.V.