Through　mixing　the　KMnO4　solution　with　K0.5Na0.5NbO3　(KNN)　powders,　cold　sintering　process　(CSP)　was　employed　to　fabricate　high-density　Mn-doped　KNN　green　pellets　and　ceramics.　The　microstructure,　doping　effect　of　Mn　and　electrical　properties　of　these　ceramics　were　studied　in　detail.　Compared　with　conventional　sintering　(CS),　the　CSP　supports　the　homogeneity　of　dopants　and　then　promotes　grain　growth　and　ceramic　densification;　thus　the　Mn-doped　KNN　ceramics　prepared　by　CSP　show　the　obviously　higher　density　and　larger　grain　size.　Besides,　the　less　alkalis　volatilization　and　oxygen　vacancies　result　in　more　Mn3+　but　less　Mn4+　in　CSP　ceramics　compared　to　CS　ones,　which　endows　the　pinning　effect　and　good　poling　characteristics　in　CSP　ceramics.　All　the　previous　results　contribute　to　the　high　dielectric　constant　and　remnant　polarization　in　CSP　ceramics,　which　support　the　enhanced　piezoelectric　coefficient　and　are　much　superior　than　Mn-doped　KNN　ceramics　prepared　by　CS.　This　work　reveals　that　CSP　can　be　a　new　doping　strategy　to　perform　chemical　modification　of　electrical　properties　in　KNN　ceramics.