A　novel　high-entropy　rare-earth　disilicate　(Yb0.25Lu0.25Sc0.25Tm0.25)2Si2O7　((4RE0.25)2Si2O7)　was　proposed　as　an　advanced　environmental　barrier　coating　(EBC)　materials　in　this　work.　The　(4RE0.25)2Si2O7　powders　were　synthesized　using　the　solid-state　sintering　method.　Based　on　the　X-ray　diffraction　(XRD)　and　scanning　electron　microscope/energy-dispersive　spectroscopy　analysis,　the　uniform　solid　solution　was　detected　in　the　(4RE0.25)2Si2O7,　which　had　a　monoclinic　β-phase　structure　in　the　space　group　of　C2/m.　The　lattice　parameter　of　the　structure　was　derived　based　on　the　Rietveld　refinement　analysis　to　the　XRD　results.　The　coefficient　of　thermal　expansion　of　the　bulk　(4RE0.25)2Si2O7　was　similar　to　that　of　the　SiC-SiC　ceramic　matrix　composite　substrate　of　the　environmental　barrier　coating.　In　addition,　this　(4RE0.25)2Si2O7　bulk　material　had　a　very　low　thermal　conductivity,　which　was　beneficial　for　the　application　of　environmental　barrier　coatings.　The　hot　water-vapor　corrosive　experiments　were　conducted　in　an　environment　of　90%　air　and　10%　H2O　at　1300°C.　The　results　indicated　a　better　water-vapor　corrosion　performance　than　the　commercialized　Yb2Si2O7　EBC　materials.　The　(4RE0.25)2Si2O7　material　prepared　in　this　work　showed　great　potential　to　work　as　the　environmental　barrier　coating.　©　2023　The　American　Ceramic　Society.