Making　lightweight　soil　with　bubbles　from　raw　soil　and　cement,　i.e.,　foamed　lightweight　soil　(FLS),　is　an　environmentally　sustainable　way　to　utilize　tailings　sand　(TS)　as　a　replacement　of　cement　in　embankment　applications,　enlightened　by　its　excess　strength.　However,　a　comprehensive　evaluation　of　its　engineering　performance　is　needed.　Thus,　this　study　develops　a　foamed　lightweight　soil　amended　with　tailings　sand　(TS-FLS)　and　explores　its　physical　and　mechanical　properties,　durability,　and　microscopic　properties.　The　results　reveal　that　the　fluidity,　volumetric　water　absorption,　and　compressive　strength　of　TS-FLS　mixtures　are　within　164-182　mm,　13.3-16.0　%,　and　0.76-1.74　MPa,　which　could　satisfy　the　requirement　of　the　embankment　applications.　After　dry-wet　cycles,　freeze-thaw　cycles,　sulfate　erosion,　and　long-term　outdoor　exposure,　most　compressive　strength　is　applicable　in　the　application　of　embankment　(＞　0.3　MPa).　Note　that　the　strength　and　durability　show　a　decreasing　trend　with　the　TS　content,　and　the　critical　content　is　less　than　50　%.　Besides,　the　increasing　TS　content　shifts　the　failure　mode　from　brittle　to　ductile　(33　%　and　40　%),　which　is　favorable　for　engineering　applications,　while　overused　content　(50　%)　decreases　the　ductile　response.　The　microstructure　observation　indicates　that　the　TS　increases　the　pore　diameter　size　and　worsens　its　uniformity,　making　the　walls　more　vulnerable　to　compression　rupture　by　stress　concentration,　thereby　increasing　water　absorption.　Moreover,　a　large　number　of　crystals　(i.e.,　secondary　gypsum　and　ettringite)　are　generated　under　sulfate　solution,　making　mechanical　properties　either　improved　by　void-filling　or　damaged　by　microstructure-destroying.　Therefore,　TS-FLS　is　promising　for　embankment　applications　when　an　appropriate　TS　content　is　chosen.