Non-aqueous　sodium-ion　batteries　(SiBs)　are　a　viable　electrochemical　energy　storage　system　for　grid　storage.　However,　the　practical　development　of　SiBs　is　hindered　mainly　by　the　sluggish　kinetics　and　interfacial　instability　of　positive-electrode　active　materials,　such　as　polyanion-type　iron-based　sulfates,　at　high　voltage.　Here,　to　circumvent　these　issues,　we　proposed　the　multiscale　interface　engineering　of　Na2.26Fe1.87(SO4)(3),　where　bulk　heterostructure　and　exposed　crystal　plane　were　tuned　to　improve　the　Na-ion　storage　performance.　Physicochemical　characterizations　and　theoretical　calculations　suggested　that　the　heterostructure　of　Na6Fe(SO4)(4)　phase　facilitated　ionic　kinetics　by　densifying　Na-ion　migration　channels　and　lowering　energy　barriers.　The　(11-2)　plane　of　Na2.26Fe1.87(SO4)(3)　promoted　the　adsorption　of　the　electrolyte　solution　ClO4-　anions　and　fluoroethylene　carbonate　molecules,　which　formed　an　inorganic-rich　Na-ion　conductive　interphase　at　the　positive　electrode.　When　tested　in　combination　with　a　presodiated　FeS/carbon-based　negative　electrode　in　laboratory-　scale　single-layer　pouch　cell　configuration,　the　Na2.26Fe1.87(SO4)(3)-based　positive　electrode　enables　an　initial　discharge　capacity　of　about　83.9　mAh　g(-1),　an　average　cell　discharge　voltage　of　2.35V　and　a　specific　capacity　retention　of　around　97%　after　40　cycles　at　24　mA　g(-1)　and　25　degrees　C.