Remote　sensing　is　unique　in　its　ability　to　record　a　variety　of　spatial　and　temporal　data　on　land　surfaces　with　complete　coverage,　especially　at　larger　spatial　scales,　and　it　has　been　shown　to　be　effective　for　rapidly　recognizing　spatio-temporal　changes　in　regional　eco-environments.　This　paper　is　the　first　to　introduce　a　new　remote　sensing-based　ecological　index　(RSEI)　to　assess　the　urban　ecological　quality.　The　RSEI　integrated　the　primary　land　surface　components　(i.e.,　the　build-up　area　and　vegetation　cover)　and　the　climate　(the　land　surface　temperature　and　land　surface　moisture)　based　on　the　framework　of　the　pressure-state-response　(PSR)　using　a　principal　components　analysis　(PCA).　In　taking　advantage　of　the　same　data　source　for　all　the　indicators,　the　RSEI　was　shown　to　be　scalable,　visualizable　and　comparable　at　different　spatio-temporal　scales,　and　it　can　avoid　the　variation　or　error　in　weight　definitions　caused　by　individual　characteristics.　We　used　Fuzhou　City　in　Fujian　Province,　south-eastern　China,　as　a　case　study,　it　showed　that　Fuzhou　demonstrated　ecological　deterioration　during　the　study　period　from　2000　to　2016,　with　its　RSEI　value　decreasing　from　0.595　in　2000　to　0.503　in　2016.　Moreover,　the　results　of　the　spatial　autocorrelation　and　semi-variance　indicated　that　there　was　a　spatial　correlation　in　the　distribution　of　the　RSEI,　with　high　clusters　at　the　edge　and　low　clusters　in　the　centre　of　the　city.　The　values　of　the　sill,　the　nugget:　sill　ratio　and　the　range　all　increased　from　2000　to　2016,　which　indicated　a　higher　spatial　autocorrelation　and　lower　spatial　heterogeneity　percentage　in　2016　than　that　in　2000　in　terms　of　the　RSEI.　Based　on　the　combination　with　the　spatial　clusters　and　the　spatiotemporal　clusters,　we　confirmed　that　the　RSEI　is　not　randomly　distributed.　Moreover,　a　hole-effect　semivariogram　was　observed,　indicating　a　high　level　of　human　intervention　in　the　study　area.　Specifically,　the　construction　of　the　build-up　area　during　the　study　period　led　to　outward　ecological　degradation,　and　urban　afforestation　promoted　environmental　quality　in　the　central　urban　area.