Dense　(K,　Na)NbO3　ceramics　are　successfully　fabricated　via　the　cold　sintering　process　at　350°C　under　a　uniaxial　pressure　of　400 MPa　for　4 h.　Equimolar　KOH　and　NaOH　solutions　were　utilized　as　a　transient　alkaline　flux.　The　microstructure　and　dielectric　properties　were　studied　in　detail.　Scanning　electron　microscope　and　the　relative　densities　reveal　dense　structures　of　the　ceramics.　After　post-annealing　at　800°C　for　1 h,　the　ceramics　show　good　electrical　performance.　The　relative　dielectric　permittivity　is　829　(at　10 kHz)　at　room　temperature,　and　the　piezoelectric　constant　(d33)　reaches　up　to　148　pC/N.　The　cold　sintering　technique　with　equimolar　KOH　and　NaOH　solutions　as　a　transient　alkaline　flux　endow　KNN　ceramics　with　excellent　dielectric　and　piezoelectric　properties,　showing　a　potential　way　to　fabricating　other　KNN-based　ceramics　at　low　temperature.　©　2021　The　American　Ceramic　Society