Cation　sites　engineering　has　been　widely　used　to　modulate　electromechanical　properties　in　potassium-sodium　niobate　(KNN)-based　lead-free　materials.　Unfortunately,　anionic　engineering,　one　of　the　effective　strategies　to　regulate　microstructure　and　optimize　properties,　has　not　been　investigated　sufficiently　in　KNN-based　ceramics.　Revealing　the　regulatory　mechanism　of　anionic　engineering　from　the　perspective　of　microstructure　is　one　of　urgent　aims,　which　can　further　enrich　the　strategies　for　tuning　the　performance　in　KNN-based　ceramics.　Here,　two　sets　of　samples　[(K0.5Na0.5)0.94Li0.06NbO3,　undoped　ceramics;　(K0.5Na0.5)0.94Li0.06NbO2.765F0.47,　F-doped　ceramics]　are　successfully　synthesized　to　reveal　the　dopant-structure-property　relationship　for　F-doped　mechanism.　The　results　of　multilevel-structure　ranging　from　micro-scale　grains,　to　nanoscale　ferroelectric　domains　and　even　to　atomic-scale　local　structure　inside　nanodomains　show　that　F　is　homogeneously　distributed　in　KNN　matrix　with　the　atomic　scale,　indicating　that　F　has　been　successfully　doped　into　O　sites.　Compared　with　undoped　samples,　the　microstructure　is　strongly　affected　by　F　substitution,　such　as　the　smaller　grain　size,　increased　TO-T,　and　decreased　VO••　defect,　and　thus　the　evolution　of　electrical　properties　can　be　ascribed　to　the　synergistic　effect　of　its　structure.　Therefore,　the　exploration　for　evolution　of　structure　and　property　caused　by　anionic　engineering　provides　a　new　thought　to　consider　how　to　tune　the　microscopic　structure　and　thus　tailor　the　electrical　properties　in　KNN-based　ceramics.　©　2022　Elsevier　B.V.