Compared　with　traditional　alloy　films,　the　thin　high-entropy　alloy　(HEA)　films　exhibit　more　excellent　mechanical　properties　and　unique　physicochemical　properties,　which　have　made　great　progress　in　the　past　14　years.　In　order　to　review　the　recent　research　progress　of　thin　HEA　films,　this　paper　first　introduces　the　preparation　technology　(sputtering　deposition,　plasma　spraying,　laser　cladding,　plasma-transferred　arc-cladding,　electrochemical　deposition　and　cathodic-arc-vapor　deposition)　of　thin　HEA　films,　elaborates　the　classification　and　characteristics　of　the　most　widely　used　sputtering　deposition　technology,　as　well　as　the　advantages　&　disadvantages　and　application　scope　of　each　technology,　and　then　summarizes　the　microstructures　and　properties　(mechanical　properties,　corrosion　resistance,　wear　resistance,　irradiation　resistance　and　high-temperature　oxidation　resistance)　of　thin　HEA　films.　HEA　is　a　kind　of　multiple　principal-element　solid　solutions,　which　breaks　the　conventional　design　criteria　of　alloy　materials　to　obtain　particular　properties　via　adding　other　alloying　elements.　Therefore,　for　thin　HEA　films,　the　microstructure　is　denser,　the　phase　structure　is　more　stable,　and　the　system　is　more　complex,　which　make　it　exhibit　many　outstanding　performances.　Finally,　this　paper　discusses　the　existing　problems　and　shortcomings　in　the　current　research,　among　which　the　main　problem　is　that　the　research　on　the　relationship　between　structure　and　performance　is　not　thorough　enough,　the　internal　mechanism　is　not　yet　clear,　so　the　research　should　focus　on　this　in　the　future.　©　2021,　Chongqing　Wujiu　Periodicals　Press.　All　rights　reserved.